backside

[4 Paws_imp]

Go talk to a local trim shop and see if they can help you out.

[crutch_imp]

I put a corbin gunfighter on mine, has a rounder "seat" area. More room for your rear and a little room to shift around as the ride goes on to get a new position. The standard seat was like a 2x4 to me, too narrow, couldn't go more than 20 minutes without being uncomfortable. I couldn't see how putting a cushion would improve it, it's still very narrow. I wanted all of my rear on the seat and not just the inner 3 inches on each side. Good luck with your search.
I'm 5'10" and 200#.
crutch