I would start with 1.5 and build it up. You adjust, I promise. (I dont have any problem at all shooting 2cc regularly)
I dont usually like to put more than 2.5 in my quads but have shot 3cc without a problem. Its really dependant on your quad size. If you've got 30in thighs, you're gonna be able to shoot more than someone with 20in thighs.
Beware though, the quads have more nerves than any other site and boy does it hurt like a bitch to hit one!
I can't wait 'till my next EOD trenbolone run...Imma use insulin pins
Chris