I tried the Save Copy In... and it worked! If you select 24-bits for your new session (coming from a 16-bit session), it automatically forces you to copy all files anyways - which makes sense. Thanks Night Train!
(I wasn't clear in how much of the recording had been done already) The benefits I can think of are at least these:
1. Although I have the guitar, drum tracks (from Drumcore) and an imported bass track at 16-bits, I don't have the final lead or background vocals, so the new vocals would benefit.
2. There will also probably be an overdubbed acoustic guitar and who knows what else (handclaps or some other live percussion).
3. The Native Instruments B4II sounds should benefit from the 24-bit resolution. VI's in general should sound better.
4. My Reverb and Delay plugins should sound better as well.
5. I THINK the plugins (EQ & Compression) on the 16-bit tracks will sound better because they now have 8 more bits with which to calculate changes and output those changes (more precision).
6. Certainly plugins on the master fader will benefit when summing tracks.
Overall, the track does sound "bigger" in the new session, but that may simply be wishful hearing....
