I just finishing a repair on a 616 special with multiple pinholes. I used vinyl wrap material that is used to detail cars with. It is very flexible and the adhesive is permanent. I was told by the auto supply people that I purchased it from that using a blow dryer on low heat will help the material fit into corners and odd shapes. So far, so good. It comes in matte black and is about 4-5 mm thick.

Doug