OK... I finished the strap and he has used it live and everything.
I haven't used craftster to host pics before, so I hope this works...
Here you can (not quite) see the leather ends are sewn on. I just hemmed the edge of the strap, then looped it thru the leather bit and sewed it shut (using very heavy duty thread and a manual "serger" like seam.
I also made it adjustable with the little slider piece, since even hemp will stretch a *little*.
Here it is in action... He's in the black t, behind the lead singer. The strap held up well... his only complaint was that I was so careful to not make the last row too tight, that it ended up a little loose. This made the foundation chain row seem too tight. We slipped a shoulder pad onto the strap to keep the edge from digging in to his skin too much. I could have reworked the last row, but he wanted to wear it the next night. A *slightly* tighter last row would have prevented that. (But it didn't SEEM too tight until the full weight of the guitar was on it, so you might want to use some heavy duty safety pins to try out the feel before you do all of your hemming.
Hope that helps!