Hi,
I've done all my last feature films with RED cameras running in real 24fps and TC was 24fps in both camera and sound recorder.
No problem at all.
All those movies were edited in FCP with a real 24fps Time Line.
Sound post was done at the very same 24fps.
Both FCPs and ProTools had 2 computer displays, no NTSC/PAL TV sets, so they could play perfectly well QTs @24fps.
Once image was locked a transfer at 25fps (yes, PAL) were asked. Then digitized. That QuickTime was conformed to 24 fps (speed change) with Cinema Tools. So a one to one relationship between negative frames and QuickTime frames was obtained.
The very same amount of frames in the neg were found in the QuickTime movie.
No problem at all.