I have a UAD, but have not got the mastering plugs.. yet. I loved the precision limiter, I was thoroughly impressed with it. the mastering EQ seemed pretty nice too, remarkably subtle and transparent, opens things up very nicely.
as for settings, the best advice I could give you is to A B.
here is some technique:
never do mastering at the end of a day's writing/mixing.
when you are ready to master some work.. take some time out to relax, listening to some CDs that you like that are in the same genre/style/vein of the music you are working on. listen to it for pleasure, maybe in a different system to your studio, in the car, and take it all in without trying to think too much about frequencies and dynamics. just get a feel for how it sits in the various systems.
then, in your main monitors, listen to this music again. set a good level and
don't touch the master fader again. bring up your mix, and let yourself react to what it is lacking in terms of frequencies, punch and space compared to the tracks you are A-B ing. dial in as much EQ as you like, wherever you like until you are getting a similar sense of frequency spread and overall loudness as the commercial tracks. of course there will be a distance between yours and the bought one, depending on how close the tracks are in style of mix. but if you are listening carefully to a few tracks and they are well chosen as guides for where you want your mix to be, you should find useful similarities.
then, if you find that to make your top end as bright as your ref tracks, you are getting nasty harshness.. this may tell you your mix needs reviewing - there may be elements in your track that are getting over-hyped and may have been over EQ'd to start off with. same goes for bottom end - if stuff just gets boomy and muddy, it needs review at the mix level. as for mids, well there is no rule there either.. except that if you are finding yourself needing to go all notchy and zone in on stuff to pull characters forward in the mix, then maybe you have a problem with your relative balances.
if none of this is coming up as problematic, then you're on to something. the key is to not touch that master volume fader between your A B listens, so that you are not instinctively turning up (or down) your track to compensate for why it does punch as loud as the ref tracks, or alternatively, why it bottoms out your speakers in comparison to the others.
then bounce away, maybe do some alternatives if you aren't sure what you like.. and take it to your other stereo systems or to a car and A B with your ref tracks again. if your music is intended for vinyl ie, for playing in clubs, then you really want to be getting into a club and listening there as well.
anyway, it's general advice and not exactly what you were looking for, but hopefully useful all the same.
have fun.