you want to hit the upper/outer quadrant, stay away from the middle area. Glute shots are harmless, specially witha 1 inch pin. sounds like you are aiming at the right spot
I use a 1 1/2 inch 21 gauge in my glutes....gets it deep. Giving yourself your first injection is scary...took me 20 mins to muster up the nerve. After you get the needle in pull back on the plunger a little bit and look for blood. If you dont see any then it is all good and push your juicey juice in slowly. Make sure to rub the area for about 2 mins after and look forward to a sore ass the next day or two.
To minimize the pain (which is pretty minor depending on your pain tolerance), slap the area with your hand a few times to numb it up a bit, then clean it with an alcohol swab. Try to stay relaxed. Follow the rest of everyone's instructions. Go for it!
i use 25g 1/5" in my glutes, once the pin breaks through the skin, it is painless and fast going in, then all you have to do is inject. I don't really like to rub my ass so I just walk around for a minute or two afterwards.