Damn those Riken non-removable thwarts eh? I've got a 5 year old Riken and the thwarts are huge, and non removable. I have found though, that when I completely suck them dry and push them out of the way onto the floor, they really don't restric how much room I have. I actually keep a little air in the one under my cooler, as it provides an additional buffer to bumps frum unda. And I REALLY like having them to paddle crew with friends. I would think twice about removing them. Though the previous owner said that a heat gun on lowest setting will melt the glue allowing you to pull them if you wish.
Dude, I'd see you on the river but I'm hardly ever out there.