A common problem. Get a girth loop, punch a
hole in it and then secure it with a rivet or a chicago screw. If the hole
is put in the right place, you can still slip it off with difficulty but not
loose it.
I have never had problems with either biothane or
leather loops rubbing.
Disclaimer: I usually use a rather loose
girth.
Ed
Ed & Wendy Hauser 2994 Mittower
Road Victor, MT 59875