In the meantime, I finished a boosted seat for yours truly on the missus' KLX. Picked up a 2nd on eBay for $100. Some of the staples were rusty and broke, so Dremeled them flat. Had a little used stock DR650 seat foam in the shed which I cut up with a electric carving knife and fine tuned it with a drum sander in a drill. Then tried to fit a generic cover I had and no way to get the wrinkles out, so I abandoned that and took it into my local upholsterer who extended the sides of the fitted original to get it on . The stock seat wasn't terrible for comfort, and should be better now with an extra 25 mm of foam, and its a bit wider. So a bit comfier, and easier on the knees when both sitting and transitioning. Looks stock too, and nearly is.