Dalton, thanks very much for the detailed explaination, and especially the photos. I really need to see something, not just read about it for the best result.
Ace and Slim, you've both made excellent tools for this task. I am assuming you have to have a tool for each size spot you plan to use, since each one has a different width.
Slim, I'm not sure what your is made from, but it looks a little more difficult to make than Aces. I've never made a thing from metal, except a lot of noise from guitars and amps!
I can really see the value of a prong punch, to help keep the holes evenly spaced.
Thanks everyone, you've inspired me to do some more practice. JD