As far as the quartering-to shot goes, I think it can be a good, deadly bow shot on many game animals, regardless of shoulder position. In this angle, you actually have a bigger vital area target than the direct frontal shot. It seems to me, that many folks think shoulder blades are made of steel. Granted, if you’re using expandable, or various multi blade broadheads, you probably should consider them as such (or maybe even titanium). But if you build an arrow that’s built for penetration (as I’ve written a bit about quite a bit previously), the shoulder of your average whitetail or mule deer-sized animal is really not much of an obstacle.