Rings, straps, and gardahitch for hanging light

[mgabel_pi]

I'm an avid climber, and use lots of climbing webbing, from thick nylon to ultra-stiff thin spectra webbing, and have never had problems with a girth hitch holding. Are you sure you're dressing the hitch well?

Yes, it's dressed properly. It holds under tension. But the webbing is so slippery and not so bendable that if I just push up a little the hitch starts to come undone. So, for for example, if I were to just put the tree huggers in a bag with the rings simply girth hitched to the webbing, the jostling around in the bag would allow the rings to fall off. Here are two pics showing proper dressing and one showing how the knot loosens, and then one illustrating my next question.

Actually, I'm not sure if the short end (not holding the load) is on the top (as I've done it) or underneath. Either way, though, the knot falls apart with my webbing.