When I visited last week, each time I rode I saw people that had to get pulled off due to size issues. Yet, a friend I spoke with later mentioned that he didn't fit very well in the test seat they have up front, but had no issues getting the restraints to latch while on the ride. My advice would be to try the test seat, and if it's borderline, it might be worth a shot.
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They do have a test seat out front. Never thought to try it out... I am a tad big and it was more snug than I would have assumed. My friend is a bit bigger than I and they had to really push down on his bar to get it to lock, but they got it.
But it also has to do with who's loading. If you have a larger guy that can push down harder on the restraint that helps. But sometimes it's a smaller girl that can't push it down any more. I've seen it where if they have another attendant on station that can push it down harder, they will call them over.