Jimzgoldfinch - My overall opinion of your process is that for any record in good condition, you're doing far too much alteration of the master music file, regardless of whether your primary objective is to get more matches or to retain as much of the quality of the source material (vinyl) as possible. Offering specific settings recommendations is something I generally don't do.
Everyone has their own set of ears, their own objectives, not to mention differences in equipment. While I have little desire to remove every nit from a recording made from vinyl, someone who didn't (as I did) grow up listening to the medium, someone who listens primarily to digital source material via earbuds may well consider any noise during quiet passages and between tracks unacceptable and do everything possible to wipe it out. For me, the only reason to remove as much noise as possible between tracks is because I believe it's an impediment to the matching process. A nit here or there within the body of a track just reminds me of its origin and I derive some pleasure from that.
Because of that, instead of a "try these settings" approach, I try to show people how they can better educate themselves, so they can have the measure of control over their process necessary to tailor it to their own needs. Apologies if what follows is long-winded. Shorter responses normally come after the first one, I promise. ;-). Just keep in mind as long as it may take to read what I write, I assure you it took me much longer to write it!
That said, less is more when it comes to capturing vinyl. There are many apps intended to "clean up" vinyl in one way or another, but I'm not aware of any that don't in the fine print make it clear that the music is, to some extent, affected by the process. Steps that involve import/export, downsampling/upsampling, etc. should also be kept to a minimum, the theory being that each unnecessary step brings with it the risk of changing the music in some way, however imperceptible.
Besides, every step takes more time - time better spent listening to music.
So if a "cleanup" process isn't absolutely necessary, I say don't use it. If you can't hear it (or if you can it doesn't really bother you), then if it can't damage your equipment, or doesn't adversely affect the matching process, forget it. If it is something that needs to be addressed, use the lowest settings possible. Default to me is a dirty word. There is no "default" when it comes to processing vinyl. Every disk is different and much is lost by allowing any process that alters the file to do so unattended. Thus, I'm not a fan of "auto" anything either.
The human ear, coupled with the human eye can do amazing things. Train them. Use them.
With that, I'll try to address each step in your process in the order you presented it.
Denoise LF -
I tried a demo copy of Denoise LF, but wasn't happy with the results. It reminded me of the results I got by using Audacity's Denoise filter, which I quickly abandoned. I understand the concept though and as I said earlier, the idea of de-emphasizing LF does make sense if it is significant enough to cause speaker damage. I believe a better way to go is to either remove the source of the LF entirely, or to prevent it from getting to the stylus. A good turntable mat, coupled with a center weight/clamp can do wonders in that regard.
Persons who have studied the waveform of a purely digital source are used to seeing true silence, a waveform devoid of all signs of the tell-tale "snake" of LF that runs throughout the music, a signature one can really obsess on if you work in Audacity a lot and work in ways that exaggerate amplitude to the max. I suspect they are more likely than I am to consider the goal making the waveform perfectly flat. I think that's where many people get into trouble when working with files sourced from vinyl.
But if you are intent on using Denoise LF, I would strongly suggest using Audacity to examine what it's actually doing by examining "before and after" spectrograms. I normally look at the first minute, a 60-second sample three minutes in, and a third one around 15 minutes in. There are reasons why I sample different sections of the record. LF noise is generally worst at the edge, but unless it's horrible (an edge warp), since it's not a representative sample, I don't use as a guide to my settings. But understanding the overall signature in the 10hz-20 Hz range is critical in those few instances where I opt to apply the Apple Low Shelf Filter (an alternative to Denoise LF).
To do this, take a good look at the plateau or hump in the spectrogram in the 10-20 Hz range. If it is well below the peak amplitude, in the -50 Db range or lower, then I wouldn't do anything to that particular album. For me, well done recordings, like those on KUDU, CTI, Sire and many others, there's simply no need to do anything other than apply the rumble filter on my preamp. If I weren't using an idler wheel drive TT, I doubt I'd need even that, as it's the drive of my TT that is the limiting factor.
Decrackle -
With respect to "Decrackle" in ClickRepair, it's intended to be used only on 78's, which have a different noise profile than Lps. Use of it on an LP may result in some noise removal, sure, but if the LP is in good condition, there's nothing it should be removing that the "DeClick" process won't. Personally, unless you are processing 78's I would leave this step out. Not only is it unnecessary, it is likely destructive when applied to Lps.
Declick -
The "Declick" in ClickRepair does not simply remove clicks and pops. The name is really quite misleading, because what the app is doing is trying to identify anything and everything that is not music and "fix" it. That means even little, soft nits that may be present throughout the recording, but are audible only in quiet passages, will often get picked up by ClickRepair.
As I said in an earlier post, if you listen to the record, or to the unprocessed sound file and only hear a few clicks, you are better off using Audacity's repair tool to manually remove them. ClickRepair will remove them too, but it removes a lot more, some of which unfortunately will be music if you're not doing a lot of work manually.
As for specific settings, there are plenty of recommendations out there and early on I tried many of them. I've read accounts that suggest that as people learn more about ClickRepair, the refinements they make to their settings generally follow the same path. They learn that ClickRepair actually has several default settings, some intended to work better on music with brass instruments, others with lots of percussion. From there they normally end up reducing the "Declick" setting further, but often don't make a similar adjustment to the "Auto" setting.
If one doesn't drop the Auto setting down significantly, they're still letting the app work largely on its own. It's easy to conclude a reduction in the Declick setting is all that's necessary, because you'll see the file process more quickly and will see fewer spots highlighted as having been "fixed" in the zoomed out waveform at the top of the window.
If you set Auto at 50 as many people do and reduce the sensitivity a little at a time, you'll certainly be rewarded by seeing the app running faster, stopping less often. For many people, that may be all they need to do, all they've got patience for. Honestly though, good as ClickRepair can be, its author is the first one to tell you it's not as good at making decisions as you are. I believe the strongest feature of the app is its ability to cue up spots that may be noise or damage and let you make your own decisions. Even in cases where you are certain a repair is warranted, you will occasionally decide you can do a better job manually than what ClickRepair proposes to do.
Reducing ClickRepair's Auto setting, so you can review practically all proposed changes is highly educational, albeit a tad frightening once you see what you've been letting the app do to your music in default mode. Try using an auto setting of six and DeClick at 50 on the silence between passages and you'll learn a lot about what true noise and damage looks like, as well as how large some of the damaged segments can be.
But do the same experiment on the very beginning of a song where the first note is solid and strong and chances are you won't like what you see. Do the same thing on a passage by your favorite sax player using the default "brass" settings, but again set Auto to 6. Check out what it's still trying to do to your favorite sax player.
You'll learn even more if you first open an unprocessed sound file of an entire album in Audacity and study the peaks, then run it through ClickRepair and study it again. If while studying the unprocessed sound file, you identified music peaks that were significantly higher than the rest (one or two hard struck individual keys on a piano, or those few times the drummer really came down hard), you may discover that during processing, ClickRepair grabbed those notes and dropped their amplitude, removed what made them stand out above all else in the music.
Once you've learned what ClickRepair, if left unattended can do to your music, obviously the next step is to figure out how best to keep it from making as many unwarranted changes as possible. To this end, I recommend using the app's "Abort" feature.
If you use breakpoints as I do, you can safely process the fraction of a second of silence before the first track in with Declick at 100 and full Auto mode. If you then drop Auto to six and click through a dozen or so proposed changes, you will see fairly quickly whether the app is going to alter more of the music than is acceptable to you. If that happens, simply hit abort, choosing the option that lets you simply start over, make adjustments to your settings and try again. Eventually you will either hit on settings you are comfortable with, or you will, as I often do, opt not to let Clickrepair process the body of the track.
A caution though. You're still only sampling the first track. While this should get you in the ballpark, every track is different and since Abort makes you start the entire process over, it's best to start every track with DeClick set very low, auto set low as well. If as you start processing you think it's safe, slowly increase your settings.
I also recommend using another feature of ClickRepair to help verify your decisions. On the upper graph, at the far right, there is a little marker that corresponds to the point ClickRepair has stopped at. Drag across that marker, then hit play and you are hearing the area in question. Assuming you're using a good set of headphones, if the proposed fix is actually noise (noise that matters) you should hear it. If you're not certain, hit the "fix" button while the segment is playing. You can toggle between "fix" and "undo" while it plays. As much as I've worked with ClickRepair, I'm still often tricked into thinking music is damage, so listening to proposed changes remains quite important.
Audacity's "Click Removal" vs. "repair" -
I don't use "click removal" ever. I tried it, but after examining the file more closely, decided the time necessary to use the "repair" function to manually make corrections was time well spent.
Audacity's "Normalize" function -
I don't use it, but I know many people have no other means of correcting channel imbalance. Instead I audition enough of each album prior to recording to know if there is an imbalance worth correcting. if it's quite obvious that uneven groove wear has caused a problem, I make adjustments using my preamp's balance control. If there isn't a readily apparent imbalance, I leave well enough alone.
I hope this helps.
