The late, great Marvin Denny, known as "Bigiron" here on the forum, was pretty darn good with Fox engines and he introduced me to the use of playing cards for back plate gaskets. The stock cork gasket is pretty think, and like you mentioned, tend to allow the ears on the back plate to bend. I had a friend of mine, who was a pit boss or supervisor at a local casino get me a few decks of cards that had been taken out of play, which they do regularly, and they use a punch to go all the way through the deck, box and all, to mark them as unusable. I can get two gaskets out of each card. Cut a card in half. Use a template to cut the big hole, then use the back plate to center and hold the gasket, but turned half way to clear the holes. Use a sharp #11 to poke a hole for the first screw, run the knife around the hole to open it up, then put one screw in. You might need a flat washer so the screw doesn't bottom out. Repeat the process with the other two holes. Remove all screws, locate the back plate as normal and install screws, then trim around the back plate with your sharp #11 blade to remove excess material. Tighten the three screws securely. The first time you run the engine the heat will cause the clear clear coat on the card to soften and act as a sealer. If the ears on your back plate are bent a bit from using the old cork gasket, tightening the screws with new gasket in place will level them back out again. Don't try to bend them with pliers.
Type at you later,
Dan McEntee
This take a whole lot longer to type than it does to actually make the gasket!!!