Yeah, I figured I'd try to help people make good stories as well as helping them avoid making bad ones. A good story and a not-bad story are very different animals.
And for that character that gestures a lot, you might be able to get away with occasional descriptions commenting on the way they move their hands. Like from your description, I'm picturing how an illusionist moves his hands around to keep people's attention and all the little flourishes he adds to "punctuate" his illusions. If I'm accurate, of course. But something like that could get the reader to expect that it will happen whenever he talks, and an occasional action after a line of dialogue reminding them of it could be enough to trick them into picturing the gestures without you having to tell them to. Just a suggestion though.