usually you can tell within a few hours that the oil didn't make it into the muscle. the area will swell and you may have a lump under your skin. my first couple pins i was scared to put the 1" all the way in my thigh and the oil got injected into my fat. the next day the oil seeped down to my knee and it swelled up like a baloon.
1" may be a bit short for glutes...i use a 1.5".
also try to time your workouts so it doesn't get effected by pip (post injection pain). for example, i pin delts on mondays cuz i dont work delts in the gym till wednesday and by then the pain is gone. i pin quads on thursday cuz i dont do legs till tuesday. PIP gets better, but for some it's still always there throughout the whole cycle, and if you pin a muscle and work that muscle right after, it makes the PIP 10X worse