[doug_hti]

I'm coming into this saying that this is completely a sytlistic thing and opinion.
But how I typically deal with stacks, (which I do quite often) can vary from song to song.
Say it's a lead stack triple...I'll widen (pan) the 2 and 3 vocal to an equal amount (maybe 50% or each side) and put the first one up the middle, experiment to figure what sounds best depending on where everything else is at in the song. If you have other Background Vocal stacks, then I widen the backgrounds All the way...The panning and how well the stacks are lined up with each other is a huge of the magic you get and how tight things sound.

As for dynamics, I do put a little more compression/limiting on backgrounds/stacks only to control the levels and make them more equal. I'm not doing it for a particular sound. On a typical compressor, I usually set it up to be more like a limiter. High threshhold, and hi ratio (like 7:1)...and pretty fast attack....

For effects and to get the stacks to sit in. I will rarely put reverb on them unless i have a huge predelay and it's subtle. The trick that has always worked for me is to use a delay timed to either a 1/8note or 1/4 note...with about a 20% feedback.
I put all my effects on their seperate aux tracks (a short delay (1/4 or 1/8), long delay (1/2note), pitch widener, reverb) and just use my sends. For some reason I think it sounds better instead of sticking on the direct track and reducing the mix level, but that's just me. I also visually have easier automation and can share the effects.
On another aux track, sometimes I put a pitch changer on it (DPP-1)...I usually put it up 9 or 10 cents and down 9 cents and a little delay on it. I don't put very much on it...never enough to deliberately notice.
With delays, I usually (when the music is playing)...I put up the delay until i can noticeably hear it and then pull it back a few db, to where I can't hear it. If done right, this can really fill out your mix without mudding it up.
I'll use 1/2 note delays on some tails and echo effects, but rarely ever just stick up to some point...
As far as EQ, I almost always put a little top end for air (like 10k or 12k) maybe 3-5 db. Sometimes I put a little bit of 4-6k by one or two dbs. And then many times if it's a heavy mix, I pull back a couple db anywhere from 150-275hz. Maybe it's pychological, but it feels like I'm get more definition in the vocals and in the instruments.
Hope some of these opinions help