That is a good point about taking the vinyl just to the edge. I would not want to pry my metal frames open. They have been powder coated and don't know if it would crack the finish.
These panels have been on the truck for years and at the time I merely painted the backs with good exterior paint.
I did at one time try to make panels from wooden door skin and they turned out okay but there are some minor curves in the door and the wood did not want to lay flat.
