I've been doing something very similar with a 14-member all female a capalla group from the University of Chicago.
We get together and record once a year.
If it's at all possible, then I would recommend just tracking as much of it live as you possibly can. Depending on how complicated the parts are, their level of rehearsal, and how picky they are ... you might consider breaking some of the parts up.
What I (we) generally do is this ...
* Vocal percussionists and soloists on their own individual mics. Separated somewhat from the group (off to the side or out in front -- whatever is reasonable).
You could use one or two of your 57's (with really good, thick wind screens / pop filters) for the VP. The Rode could serve as the lead vocal mic ... with the girls stepping up to it when necessary, depending on the arrangement.
* Pair of SDC's in XY -- or even a mock binaural arrangement ... and have the girls circle around the stereo pair ... if you separate them somewhat with bass/alto on one side (facing the "X" mic) and everyone else on the other, you can get some really nice stereo spread.
Once you complete initial tracking using this setup ... you could go through it all with the girls, and pick the ones that came out really well and designate those as keepers. And anything else you can either re-track using the same method or divide them up in to groups and track each section ... using the initial vocal percussion tracks as a guide track ... and then overdubbing each part / section one at a time, with the lead vocal last.
Word of warning: What usually winds up happening is the soloists will hate their voices and make excuses for how poor their performance was ... a few will probably break in to tears, etc.
And they'll want to re-track their vocals ... which will be impossible due to the amount of bleed (of their voice) from the initial tracks. To avoid this problem, you can track the lead vocalist (s) in a separate room during the initial tracking ... which presents you with the ultra fun task of getting headphones mixes for 14 girls! Fun stuff.
Right now, you're probably thinking how great it's going to be working with 14 college age girls. But when all is said in done ... just be sure to keep several bottles of aspirin on hand.
College girls like to talk. And they like to talk loud. They also like to talk at the same time, so you could have as much as seven different conversations going on at once. And they basically talk about stuff that isn't all that interesting to anyone who isn't a college girl themselves.
The only really tricky part is getting them all to stop talking at the same time. They have no difficulty
starting the simultaneous talking, ironically enough. The key is to make sure they designate ONE person to be the producer / leader. And that person has to have a strong personality (good idea if it's the oldest one in the group). It can turn in to a 14-headed monster really quick if you're not careful.
Did I cover everything okay?
