>>4172972This is something I'm interested in, so butting into your conversation, OP.
If you're American, get 100', half-inch thick from home depot. It'll run you about $30.
Do the harness you posted in your original pic. It's fun on boys, too (am a boy and have been on both sides of it). It has a little squeeze on the testicles and a little spread on the ass. Also, if you have lots of rope, he can do as many of the diamonds on it as he wants.
It's a good harness for amateurs, because it's really easy to do, and looks really complicated and sexy.
Easiest way for him to finish off any extra rope is to just wrap your arms together with thick cords, then tie around/between the wrap. Very limiting for arm movement, and the rest of the harness looks and feels great.