I have a 2017 Thor Axis 25.2 and the angle of the front seat bottoms sucked from the factory. The driver's seat wasn't too bad, but the passenger seat felt like you were being tipped forward. Today I did a cheap and easy fix.
I went to Tractor Supply and bought four 5/16"-18 X 2" long bolts and 4" of 1/4" washers. I painters-taped the washers into four separate one inch bundles, removed the existing seat bolts, put a bundle of washers on each side in the front between the seats and the slide mechanism, and sent the newly purchased bolts through the washers into the seat bottoms. THE SEATS NOW FEEL FANTASTIC!
NOTE: If you are going to do this, I would strongly suggest that you tape up the seat skirts to keep them out of the way as you work, and be careful of sharp metal edges under the seats.