Basically everthing Moe said I agree with. In saying that, I've always had my suspicions those who have larger bums Have had a harder time of it getting the Corbin to perform to the standard they expect. I did cross this exact subject several years ago butt (sorry), I didn't get many takers who have been honest with themselves for any concensus. I am thinking having Corbin do some alterations is a good suggestion though. Personally I would be persevering cos once it's right and conforms to you (not the other way round), you'll be forever grateful you persevered. Keep in mind though I'm in the skinnier bum brigade and can't
Comment on your shape. As far as a backrest goes, I wouldn't be without one in a million years. I'm hoping if you persevere the rewards will be there for you. After all, just how important is a great seat???