Just wanted to post a recent update to this thread, as I read through most all of it before my trip as I worried about my size. I've been on this ride three times now, once during previews, once almost a year ago, and once this weekend. I'm 5'5 and was probably around 280 when I first rode during previews. I grew up dancing and have always had large calves (even when I was a size 0 as a teenager, I could never wear boots). The first ride, they spent a LOT of time trying to figure out how to close the leg restraints. It finally worked, but it took two CMs and a lot of trial and error.
I rode again this weekend, at 5'5, 300 pounds. 2x top, 26 bottoms. A CM did have to come close both the legs and back restraints, but it was literally a touch, not a huge push. And I fit. I think as time has gone on they've found what positioning works for most people and it's gotten easier to help larger guests like me fit.