I've commenced my seat rebuild based on advice from Tony H and Oleseahorse. I've got the foam out of the donor seat and it's in fair shape although the seatback is halfway split out where it contacts the frame rails. Tony shows a method to reinforce these areas but I'm not sure what kind of material (cloth?) that is recommended as the reinforcing material, although the article does mention the type of spray adhesive used. I've got some gorilla tape which is fiber reinforced duct tape but I think another type of repair to reinforce these areas would be better.