I loved the kensington expert mouse for that (the old one that was exactly same as a poolball) since it had wonderful heft and could do both palm spins and precision one hand.

But, they stopped producing that particular kind (they were also hard to maintain using a special key to open the case) so I just switched to using my left hand for the mouse on half my computers and right hand on the other half. That was easier than moving equipment around from machine to machine for me and coworkers/family. No RSI since.