I prefer to use the quad muscle but it is a little harder to get yourself to relax totally and not jump. as far as pins go I think a little bit longer ones are better so that i can have more not stuck in while making good deep penetration in to the muscle. just in case one were to break off or something wierd like that that way i have some left over to pull it out. (never happened to me but ive read about it happening) better safe with all of this than sorry.