I started to take a crack at it yesterday, but I had tightened the bolt so much during my first attempt to get rid of the jiggle that it isn't coming off now without some serious coaxing.
The bolt is soft enough and a T-40 Torx is loose enough that I'm going to have to be real careful with my approach. My next larger bit is a T-45, and that is entirely too big. It needs something around a T-42. I even tried going at it from the nut, but light hammering on the wrench wasn't getting it to move either. I'm going to put an extension over the wrench (hammering with a mallet if I need to). Just needs some leverage; I'll get it off, but what a pain.
So I guess the lesson is to not crank down on this bolt like a madman because it won't stop the wiggle and you'll create more work for yourself.