I had the same issue with my bottom(s) and got great results by finding a local upholstery shop and had them replace that outer panel for $50-60. Toughest part was finding a matching material to OEM. I also added extra cushion material (find a local foam shop... usually the upholsterer will know where to find foam). I live in Reno and there's a cottage industry of restoring classic rides... Hot August Nites, and other events in town create some of the best restorers available soooo that helps sleps like me who are just looking for the basics. Good luck
Chuck
P. S. I don't have the TDR issue # for the seat improvement but it was very basic. Remove seat bottom, disengage the spring bottom and add some low nap carpet squares and re-install. Helps a great deal. You can add extra foam, etc on the outside edges to give you bolster on the sides. It'll never be like a custom seat (recaro or other products) but I re-do mine every two years or so.