Play in the risers?!? Then there is something wrong! There shouldn't be play in a riser no matter how tall they are.
I have Rivco's on my R3 and there is no difference in the "play" from the factory risers.
You might want to recheck your torque, sounds like something isn't right.
Classic pull back bars will fit without the longer cables as I never changed mine. Now that I will be add reversed Rivco risers to the classic pull back bars to make room for a steering dampener I will have to change the cables but hey they are easy to change.