delts.. do your delts.. they are usually the LEAST painful area as far as post injection pain..
also you can try cutting it w/ a sterile oil but that really doesnt help alot.. honestly i would just do 1 big shot of 3cc /wk like every sunday.. just do 3cc in your glute or delt.. the pain will last about as long as it would if you did 1.5cc but you only have to do it once a week.
as far as volume goes.. psh 3ml isnt alot to worry about.. u can usualy put up to 4-5ml in a glute and 3-4 in a delt if you have a deacent muscle build on ya plus the stretching of the myofascia is always good