I want to print a set of these on my 3d Printer, and can't find a good .stl file for some already made up... so I'm going to make my own file, but I am wondering if anyone has the dimensions on these? The diameter of the wide rings in the center, how high the heads are etc? I know length doesn't matter so much since they are hidden by the pocket, but I don't want the heads to be crazy disproportionate.