i dont know what advice has been givin to u, but what i have read and been told is to go all the way in, the more u keep the needle out the harder it is to keep it in place, well for me atleast
There's some good basic info in the "info" section but it really doesn't show you much in the way of specific places within the muscle to inject ie. the different heads. It's just some dude sticking a needle randomly into a muscle other than his glute...