I think that an IM inject is just more consistent. You don't have to worry about getting it into the fat vs under the skin, especailly if you're lean. The shot is going to be the same every time. I have recently read a study saying that plasma levels didn't really change between either IM or sub q, but I'll stick with IM.

As for what needle, I just load up an insulin pin. I ususally use a .5cc with 29g pin and stick a tricep or a delt. Somewhere with lower body fat.