gh pin

What gauge needle is best for sub-q injections i have read anywhere from 27-31, also what size syringe should be used? i am also a little confused about injections, i understand that i am supposed to pinch the shkin and pull it back but then do i inject in to the skin that i am pinching or on the underside, where is the pocket? that i am supposed to inject into?

i use 29 gauge half inch insulin needles. i think they r 1cc so 100ius. ya just inject in the skin u r pinching, u can basically do it anyway u want just make sure its in fat.