I have learned to love both the delts and quads. I can put 3ml in each delt but usually keep it to 2 if possible, just more comfortable. I can fit 3-4 ml in a couple different sections of my quad now (about a hand length up from my knee and a hand length down from my waist are the 2 spots I utilize.
Ever since I've started heating up the oil prior to injection I've had ZERO pain the next day....even with 3cc of prop in the quad, nothing. I would highly recommend to all that you heat up your gear prior to injection. For me, I'll heat some water up pretty damn hot in the micro and then let the gear-filled syringe sit in the water for a couple minutes. This also makes the oil slide in much smoother.