First, Let me say ,the new place looks great!! The information I find in this and the other forums here is just amazing!!
I did a collection of R&B tunes for an old friend last year and he can really sing. We dumped the synth tracks down to two tracks on the DA-88's { this was the whole music track} and that left 22 tracks for big lush back ground vocals. As mentioned above, look out for the bottom end building up with this many tracks. I to went for some "big air" up top. I chose 15-k shelving for this and was very happy.One thing that ended up being a problem was the "S's" and breaths. I didn't want to do away with them all together but, having all 20 or so tracks breathing at the same time was a drag. I ended up dumping some of them into cool edit and taking out the breaths,while leaving one or two tracks per part alone.This way, the breaths sounded natural but they didn't overwhelm the track. I then put them in a stereo buss with the following. A Harris AGC followed by a Harris FM limiter. This is an old broadcast chain I got from my dad and it gives stuff the airy,big compressed sound. I have also put multi tracked country guitar busses through this chain and it sounds all "finished". I have really been into bussing stuff in stereo a lot lately instead of using individual comps on stuff. The big thing about big lush back ground vocals is, some of what we do to get them Big and lush,seems counter intuitive. Don't be afraid to beat them into submission with EQ and compression!!