When I repanled my spit, on new homemade boards, I glued some 1/8 inch closed cell foam (white packing material) directly to the front of the boards. I then cut the black vinyl to fit the panel with about 3 -4 inches extra all around. I then applied contact cement (lepages or gorrila glue both work, I used gorilla glue) from the bottle with a brush, let the glue dry for 15 minutes, streched and fitted the vinyl, put some clamps on it, and by the time I had finished placing the last bit of vinyl, I could remove the clamps and it was done. The foam provided a bit of noise reduction and some puffyness to the door. When I attached the hardware, I simply cut with an exacto knife. The door looked great and the vinyl did not sag for the 2 years after that I owned the car. NOTE I DID NOT GLUE THE VINYL TO THE FOAM, BUT THE FOAM WAS GLUED TO THE PANEL.