I have to admit I am a little concerned about the situation I am 511 and a size 22/24 I am working on losing weight I guess one thing I have going for me is that I have no rear end so I can scoop all the way back in the seat I will keep my fingers Rip Ride Rockit is the one I really want to ride
Just make sure to get the modified seating, that would definitely help!
The last time I went on it I ended up doing single rider and when it was my turn, they put me in a non-modified seat. Normally, in single rider they will put you where they need you, but if they notice you need modified, they will put you in the modified row and get someone else to fill the single rider spot. However, in this case they either didn't notice, or just wanted to fill that spot and I went into a non-modified seat and with a huge push the guy got me in. It was extremely uncomfortable (almost painful), but I rode it to please my cousins. Normally, they try, but do not try with the capacity this guy did. Normally, (on most rides) I need a tiny nudge and I'm comfortable in, but this was different.
In my personal opinion, it seems that RRR is probably the smallest seat ride. I say this, because the few times I've rode it, I notice that people that are extremely skinny are the only ones that have it closed all the way. Technically, you can have it opened a little bit, but like other rides, there is obviously a limit to that opening and people who are only a little bit bigger (about average) can fit comfortably. Also, I noticed this gentleman that helped me the last time I rode that he had to do this ("huge push" I spoke of earlier) to several people who I have to say were not nearly as "Pooh" shaped as me. So, I didn't take that much offense, but then again, I never do.
I have to warn you that someone might not try as hard as that guy who helped me that one day and there is a chance they might walk you off. I say this, as while I am shorter than you, I am about the same size as you. Also, saying this, because (for example) one day, I went on FJ no problem and a little later I tried to go on, but because the loader was different and would not help me at all, I couldn't go on. So, it can also be hit, or miss depending on if they help, or not.
That being said, I know you say that RRR is the only ride you really care about, but I have to say if you miss it, do not feel too saddened. I'm a roller coaster fan and while it's good, it's not the ultimate roller coaster of all time, can kind of be rough on you, and I feel the ride is a little over rated. I do not want to downplay the ride too much, especially since you're excited for it, but I just felt the need to say that in case you can't go on, but I believe that you can do it with a nudge, especially if you do modified! And yay for you not having a butt I'm sure that will help! I don't have one either!