Straight and clean will work for me, I'll have to get you to do some authenticity checks for me, though.
You can make it one stereo file, panning one track left and the other right, but that doesn't seem to save you any on the filesize. Two mono trax is preferred, that way I don't have to split the stereo track on my end.
As far as syncing goes, what I try to do is produce a file that is the exact same length as the reference track. I can always trim and or slide things around if it doesn't sync, tho.
Queue