Except you need to sync start points before you can determine if drift is even an issue, and then, even if it is a problem at least I can get an idea over a song or two of where to go with it before the drift becomes aparent. Again, it's mostly for a quick-dirty playback check in that case without the computer. For the real deal, I align and stretch/shrink to match with Samplitude's Elastic Audio feature.
I use the R-44 this way sometimes as a 4 channel surround playback machine and a channel delay would be welcome. I'd do the same with the DR-680 for 5 or 6 channels.
BTW, a typical delay effect unit can do the 'lag-time' job, as long as it is set for a single delay and 100% wet output with no through dry signal. That way only the delayed signal is output, instead of dry + delayed echo.
Anyway, thanks for letting me know and apologies for the side track..