What a genius he was, and it seems he was great fun to be around. The third part of this item on him and Gene Krupa shows him at work with students. It seems he enjoyed getting the best out of them as well.
I was expecting that he'd play his hi-hat open-handed with having it so low so as to get over to the extra floor tomtom on the left of the kit. He didn't though, according to this clip: