How long is the needle and where are you planning to pin? 23G is okay, it's what i used my first two whole cycles, i'm about to try 25G, if you've got body fat i'd say 1.5 for glutes, no body fat you can use a 1 inch, in shoulders aswell, 1 inches are fine with body fat & with low body fat, & you can use 5/8 in delts also