The Whammy is a great rest for a single cam bow. I have had it on Binary cam bows with parallell limbs and they can be a bugger to time. if at all. Spott Hogg will have more info if you call them. They can tell you what bows are not compatible w/ the Whammy.
There was a redesign this year that took care of some of the timing issues, but I would still call.