RE: My addiction just made me buy a piper cub, now i have q's?
The .46 will be plenty. Even with the clipped wing, it will have a lot of lift. Cubs fly slow, using lift from the wing; they aren't shot through the sky with thrust from the engine.
As for the roll problem, make sure the ailerons are centered correctly, the rudder is straight, the wings aren't warped and so on. Also verify that the CG is correct, that could be all you are dealing with.
The prop you are running should be fine. You should be turning well over 10,000 RPM though, probably closer to 12,000-13,000. Unless it is a 15 pound brick, I really doubt weight is an issue either.