Interesting about the rpm limit. I remember agk and scotto playing with the springs in the 'verters to get it to engage at different rpm's. Even using spacers to keep it from going into "super-overdrive" to get the rpms higher.
I found this one thread on the subject http://motorbicycling.com/showthread.php?t=39609
, but there's gotta be others to be found with the search.
Sounds like you'll be doing a lot of test driving and taking notes