The Fisher Body manuals only really mention that you insert clay block or similar, slightly close door to leave impression and adjust to suit. I guess you could do similar with a smear of grease and see where it touches. I also have the thin mylar disc shims, makes any adjustments easy and no chance of scratching paint. Be aware that the original GM striker used a specific tool prior to the Torx type becoming common and are not the same, GM version had square shoulder ends. Reproductions could use anything, even allen key on some.
