[GW]

Do you use so many harmony parts because this is exactly what you want to do OR do you need to do this to cover any artificaility?

Yes, I want to, it acctually sounds better, when you use fewer parts...

Would you say that the quality (once you've finished tweaking) is that good that no one would ever suspect that it was anything other than an additional human voice?

Real session singers are better - but before you have transported them, fed them and made them sing in pitch from the scores you have written, it has either cost you a lot of money or you have called in a bunch of favours... ;-). These guys doesn´t have to go home to take there girlfriend to the movie, they just sing on nomatter how late it is (or early).

By the way, what is "MD3

MD3 is an overpriced, but extremely good limiter/compressor from the System 6000 ported in a stereo version to PowerCore. Use it with Harmony4 and increas the Headroom and it just sounds much better then Waves... You can actually get a Singers Unlimited feeling in your acapella takes.