Hi and thanks,
I really appreciate your help - I managed to first of all realize I shouldn't be having the problems I was having (freezes after a couple of minor tweaks) and then how things should be organized. Which lead to figuring out what the real problem was (drive failure!!) and on the road to fixing it. A bit of history: I began using Aperture 1 with everything on an external drive (yes, bad idea) thinking the images would fill the internal drive and that would be the way to handle it - yeah, they probably had referenced-masters libraries back then too, but I didn't notice...
Now I have the library and all the images on the internal drive on my iMac - because I have a 1T drive and, at the moment, they fit. The plan is to move to referenced images on an external drive, library on internal drive.
Why? because it turns out a big part of my problem was an external drive failure. The drive with my main Aperture library on it failed. I was .. sort of.. able to recover it (note to self: don't bother paying for data recovery, just use the vault) but chunks of info were missing so ended recovering using the vault anyway. The new drive is LaCie d2 quadra 7200 rpm w. FW800.
Right now I'm waiting for some time in my work flow - after losing tons of time with this problem (downloading/uploading entire library over and over, for one thing) - to move images to another drive and set up a referenced masters library. BUT first I have to work out a backup system for those images. So they're filling up my internal drive for the moment - but being backed up with vaults and time machine. Hey, at least it's working!!!! and backed up.
Mucho thanks everyone.