hehe... Pooh sized... I like that.
I'm the shortest of my friends and yet the... fluffier of them (well not anymore, but the last time we went to the park I was). 5'2" 200 lbs. and I didn't have any problems really with any rides.
I've already gotten used to arching up to get the seatbelts done before sitting my bum down in the seat, so that was never a problem. And alot of times I feel more comfortable when the bars or shoulder restraints are tighter (makes me feel like I won't fall out).
The only kinds of seats I found to be a little uncomfortable (until you get into the ride and forget about it) are the seats that are bucket-seat style. Those are made for people with small to moderate sized bums... and most of my fluff is placed right on my bum.
And at the OTHER park... the only ride that I was oncomfortable on (but still worth it) is the E.T. ride... it's supposed to be kinda like a bycicle but it's like a bucket-style bicycle seat almost.
Yeah.... so that's it.