The seat on the 650 I have is of similar design and I have the same issues. I recovered mine with a stock pattern cover (eBay) with minor difficulty. The seat pans are not easy to change but a a competent shop could modify the foam and sew a new cover to fit,, for several hundred dollars is my guess. That's why I compromised, as well as maintained originality. It's not terribly uncomfortable for the distances I use the bike for. The cover I got is good vinyl fabric and attached with narrow crown air staple gun. Short staples,, had to order thousands as I recall but cheap. Has held up well and decent looking.