I recently began making the shoulder holster in Stohlman's How To Make Holsters Book. I have the holster support all cut out, however it is to small. So two questions have popped up. What is the proper way to measure for proper fit? Is it possible to merely lengthen the strap that goes over the shoulder to solve the problem? This is my first attempt at making a shoulder holster, so any advice I can get is appreciated. Thanks, Steve.