i suggest positioning your strap so that the end pin of your guitar is within 5 inches of the top of your hip bone. this is how high or low it is, not the actual proximity to your hip bone.

i angle my guitar so that it's angled up. this makes it easier on my picking hand because it's lower and then the fretboard is angled up so it's easier fretting. it works pretty good for me, and it works in a live setting and not just standing still. i highly recommend it, i've been using it a lot and it's highly effective.