And if one side of the elevator jams up or down, is it dangerous to try to offset it with the other side after the split? Even if the jammed side is at neutral, presumably you'll need relatively large deflections on the other side to get reasonable control authority.
As SLF, though, I wonder what the procedure is for flying with split controls (absent a jam). I'm guessing that one side is normally left at neutral, and both pilots don't need to constantly try to synch inputs?