Why not just go to a upholsterer. You pick out the material you want, cloth, vinal, leather, etc. They remove the old cover and use it for a patten. The add or replace deflated foam and can have clear plastic covers made also -
Just buy some new captain chairs with the options you want, i.e. massage, heat, electric adjustment, high back, air suspension, recliner, etc.
It is your bum and back that are filling the seat for extended periods, so why not be comfortable and spoil yourself.