If photo bucket wasn't such a PIA I'd post a pic of a template that that I use. It's basically T shaped and folds over loop of string. However it takes a pretty stout leather as the leather is what keeps the bow limb from poking through the loop and sliding down the limb. I wouldn't doubt there is a build along somewhere or even a You tube on it. I even customize it so one limb tip is smaller than the other so you can easily slip string in limb grooves. Like I said I much prefer this type stringer rather than the wedge that pulls on the limb.
Once again terrific work! I try to make as much of my own stuff as possible or end up customizing pretty much everything I own. This winter I've made (7) 440C hunter knives and sheaths, did a European mount of my bow killed 8pt, processed some turkey wings into fletching and made a electro etch machine for knife marking. I also do my own taxidermy, make my own recurves, strings, etc Winter is when I fire up the wood burner in my garage and make stuff. Summer times there is too much to do outside!