There are numerous types of seat foam you can use. Search the past articles to find vendor. I used three different density’s. Trial and error. Glue together with low strength 3M spray glue for initial fitting. I like extra lumbar support so I
added that. Trim width and length to clear stick, flap handle, etc. Get in and out to check height and comfort. Then take to upholstry shop and have a plain cloth cover installed. Then install in aircraft and sit in for at least an hour. Try all controls and canopy clearance. When satisfied take seat apart and reglue with high strength 3M spray glue. Cover with your favorite material and you are done. Sections of Velcro hold them in. Takes at least 20 hours.
Bob Grigsby. RV3B. Almost done. two steps forward. 1.5 steps back