Ended up with some rubber feet instead of the teflon ones. After I installed them, I had to adjust the back metal strips in the back to allow fer clearance when the trailer slides/wiggles in the back. The feet promptly snagged the flashing protection and ripped up one edge. Guess I'm going without any sort of protection on top. Maybe some grease will help?
No noise from the feet as far as I can tell. Looks like it's a keeper.