Hope you are able to swing by the ride. If it's like most other rides I've gone on, yes, a great deal of people will be on the thin side, but far from all of them. There's an entire section for those of us that don't fit into the Olympic althlete physique -
Clydesdales/Athenas exlcusively for those over 91Kg (200Lb).
Have to also suggest you check the
Tom Stormcrowe the lead administrator's page for some inspiration. It's mind over matter, as long as you don't mind, it doesnt' matter.
Best of luck