TLW -   I think you have the idea of what I'm trying to pull off...    Thanks for the heads up on any reverb on the backing tracks - and yes -  my intention was to absolutely have each voice going to an independent track.   And I'm afraid I will have to use cans for the best results,  I can see that going over with great enthusiasm.
 
Since I don't have 4 input capability for Sonar ( 2 in 4 out )    I figured I would use my 4 track fostex HD recorder and import those wav files   ( at least try it at home and see if it flies. ) 
 
I also plan to record the individual parts in short takes with each phrase or subject line per take.     Since it's Handle,  that concept should be very forgiving, and inherently easier to deal with in the long run  especially allowing for  performance issues such as phrasing, tone, diction, etc without having to record long sections of music.
 
Thanks again for all of the input.   I need to work on recording a basic acc. track and I'll post an update in a week or so and let you know if they all revolted!
 
BTW,  the recorded accompaniment track will be basically harpsichord in nature, and the live performance will be with with organ.    ( easier said then done,   I know...   Ive done this part before! )  
 
I will say, the addition of the "Big Time View"  along with a solid bass line is a life saver in the later versions of Sonar.
WG
 

I think you've received much better recording advice for this music from the others (who are experienced in such things... everything I said was purely theoretical guesswork) but they may have indeed glossed over the need for 4 vocalists to cover material written for much more vocalists (like harmonies, group vocals, etc).
 
Not entirely though. They allude to ways to get those extra harmonies and doubles in there.
 
It's a shame to waste a good natural cathedral recording environment but since you are going to be layering performances a dry/small room/close mic recordings of each vocalist performing differnt parts and/or using pitch shifting to create the harmonies, to me, would be a more flexible and manageable approach. Note: If the vocalists can record the extra parts properly it would be way better than pitch shifting.
 
Harmonies are recorded like this all the time for commercial stuff using a single vocalist (I've done it myself back when I actually recorded my own vocals). With close micing in a dry(er) room, layering the parts/harmonies with multiple passes (and making sure to get multiple takes) you can do a ton of stuff in post production.
 
With just that you can correct the individual close mic'd takes as needed and then add virtual room reverb to mimic the cathedral.
 
Then maybe do some takes of the whole choir IN the Cathedral to blend in... or maybe even start with those as bed tracks for the dry close mic recordings for your singers to track to. So record the whole group in the cathedral together, maybe with more of a room mic set up for a couple takes/harmony variations. Then record each singer close mic's in a dryer environment (like a smaller room or in isolation one at a time).
 
Use the cathedral recording as a reference to the room sound and go through the mountains of convolution reverbs (or just tweak non convo reverbs/delays to match it as best as possible) then blend it all to taste.
 
If you get all the parts, in time, in all these various configurations you can do pretty much anything you want in post production.
 
Another thing to consider is maybe if your mics aren't all the same then try switching around the mics between the vocalists to get a take of each singer on each mic which might provide some nice variation for group vocal dynamics (like the same part sung multiple times through different mics mic give the illusion of more/different singers instead of the same singer through the same mic every time).
 
Panning/EQ/chorus and stereo effects can help fill out the "full" choir sound as well (again something that can be played with in post prod if you have enough takes from everyone).
 
Using pitch correction/humanization on the same tracks to acheive the choir effect really isn't going to be as good as actually getting the singers to perform the doubles/harmonies so get as many as you can.
 
Sounds like you may only have access to them for brief time (which is usually the case with live tracking) so do what you can with the artists while you have them. If some have to leave but others can stick around (or maybe you can get extra sessions with anyone later) just keep going until throats are raw or it's time for nature to take over (food/sleep/etc).
 
Again... just some THEORETICAL thoughts from a non pro.
 
The other fellows who have commenting have actually recorded this type of stuff so pay close attention to the techniques they described to actually capture the sound.
 
Cheers and have fun.
 
Edit: and yes... tlw was totally rocking the concept. He's a smart dude.

Don't underestimate yourself Beepster, you gave some very good advice.

It just happens that I've experimented with pre-recorded backings a few times over the years. Some of the most experimental experiments years ago were actual gigs, and I have the scars to prove it. You know how it goes, the average gigs you forget, the good ones you mostly forget but the nightmare ones are burned into your memory for ever.

Computers make using backings far easier than it used to be though. I've never got my head around Live, I find the interface completely unintuitive, but I've seen people do remarkable things with it. It's something you have to practice to death though because anything that hasn't bitten you in rehearsal almost certainly will on the night.

http://stabilitynetwork.blob.core.windows.net/g-tunes/20120916_G_DayByDay.mp3
 
This was one of these recordings I mentioned above.

TLW...    Amen to that.   I originally fired up Cakewalk Sonar to do more "contemporary" stuff to be combined with kids...    Then it really got to be fun when last Christmas I decided to work on  what my classical pianist son called " Dad's one man Renaissance Festival" as everyone in the whole house heard  Gaudete over and over until all hours of the morning for a solid week. 
 
It was very cool...   I enjoyed the heck out of it and the real challenge for the choir was staying focused and keeping it together during a rhythmic drop kick key change that fell out of nowhere with a syncopated accented off-beat rhythm section that lead back into the final chorus. 
 
I did it with oboe, lute, various drums, triangles, and small cymbals.  It was a blast and they pulled it off like they owned it,  as we all know...   the computer waits for no one.  
 
Of course,  there was no need for any vocal backing track last year.  I had 2 laser beam sopranos and 8 strong voices.    Well, so much for pulling in ringers that have gone off to college!  Thanks for the ideas...    I've basically clued them in that we will try recording ourselves and making our own "virtual choir".   I know they are probably thinking this is not going to be anywhere near as much fun as last year!    I think they may end being surprised once I can get them over the hurdle of the initial first set of tracks.
 
WG.
 
 
 

GSWITZ....
These are a couple of the recordings from that session...
http://stabilitynetwork.blob.core.windows.net/g-tunes/20141130_David_18.mp3
http://stabilitynetwork.blob.core.windows.net/g-tunes/20141130_David_20.mp3
 
Nice work...  Speaking of Laser Beam Sopranos....     ahhhhh!   
Send me a private note ----  who and where is this?
 
Wayne

The performance was at St. Paul's Church in Richmond Va
http://www.stpaulsrva.org/about/history/
 
It was an evening service near Christmas that started near sunset in an atrium and they sang until it was completely dark while the listeners sat on the walls holding candles.
 
When it was over, I dashed to move mics before people stumbled out in the dark.

Interesting stuff in the above posts and nice MP3's.
 
That's the inherent problem in a church band, orchestra, choir..... people always coming and going.  Kids leave to go to college just as they are really getting good at what they do, old folks retiring or moving.... it's a constant and ongoing struggle for the music ministers in modern churches.
 
The obvious solution to the small 4 voice choir is of course to recruit more people who can hold a tune to join.  Barring that, there is an amazing amount of ground, musically speaking, that can be covered by 4 voices.  Much of the modern church's  music can easily be covered with 4 or less voices. However, that also involves the use of musical instruments. Since the 2 mp3's you posted were examples of straight up vocal choir with no instruments...I'm guessing it's a safe assumption that the mp3's represent the sound you are trying to achieve. If you're going for the classic large choir singing without musical accompaniment , that really does need more bodies on the platform, singing the parts. You have no choice but to get busy recruiting more folks to join the fun. I think it would be less work on everyone involved to get more folks. Asking the existing volunteers to spend the time to learn 2 different parts (or more) and record them..... or for you to try to use Melodyne to create the tracks will end badly.... you're headed for a fast burnout from either the choir members or you from being overworked. Most folks have a limited amount of time to devote to volunteer projects such as choir.
 
While it is possible to create vocal backing tracks to double or triple the number of voices, I would stay away from using melodyne to transpose them into harmony parts.  For one, that's a huge amount of work on everyone as I pointed out.  Second, when you start moving tones more than a whole step as you would likely be doing to create harmony parts, you will start to notice the artifacts. IHMO, it's better to run with 4 voices singing solid parts than to try to emulate a larger choir filled with artifacts.  Third, using tracks "locks you in" to a particular performance. You can't easily vary or extend the song if "the spirit moves" you to do so. ( not that choirs tend to "wing it" often)
 
So, that's just my 2 cents on the topic.
 
Recruit, Rebuild, Rejoice.

Guitar Hacker....   GSWITS' recordings of St. Paul's Choral performance is way above melodyne's paygrade! 
 

Guitar Hacker,  Oh,  I'm sorry,  no...  We're doing nothing like that -   the sound I'm trying to achieve is a chorus from the Messiah.  Baroque and contrapuntal in nature.  typically performed with 8 -16 people with the theme constantly presented in one part or another with a lot of inverted harmonies.    All of parts have solo lines that thread in and out meeting in 4 voice cadences,  and it's not quite as difficult as it "sounds".   
 
It's one of those works that stays with you like riding a bicycle.