I don't think its a good idea to inject that much in one spot. I think some one on here got an infection by doing something like that I could be wrong though. I would try to stay under 2ml's in any injection site.
you can inject 5 ml into every spot if you have decent muscle mass and work up to it
just dont use test prop lol
a high amount of oil with lower concentration gear actually feel much less painful than a tiny injection of high concentrated gear.