Glen, I have 2 short risers and one long. It is very hard to tell the difference. The long riser is my newest so of course it is the one I am shooting the most right now and "feels" the best. One day this spring I have to line them all up, set up the chrono, and do some testing.
As far as lefties go, I know he had one at the Trad Expo last weekend. It may have sold, I'd call or send a note. My buddy picked up a LH TT Longbow at Kalamazoo and he cant put it down. See here:
TT Longbow thread