I have found that the adjustment holes for the seats are actually slots, and allow for inward/outward afjustment of the seat towers.  I have a quite large ass, (ghetto type)and I am still having some issues, but Dinver is working with me to resolve the issue.  

First thing though, dont let a seat be a reason you get rid of a boat. its like selling a car becuase the volume know on the radio isnt the way you like it.  there are adjustments you can do.  even removing the seat entirely and making your own seat...

Good luck!

Mike