i wouldn't go over two cc's per delt, i just pick the outer most point of my side delt, or the side peak if you will which is pretty much the center or my shoulder and inject there, i do delts at least 5 times a week now(on fina), i have been using them for over a year now, i think its definitely helped widen out my shoulders and its the most painless place i've injected. I use a 25g 1" and have never had any problems.