Ive used 2mls in my bi's without any problems. WV, deca, test, Eq, etc - all with no problems. The higher concentrated drugs (test @250mg per ml) hurt a little more then the lower concentrated drugs (WV @ 50mg per ml). Im not sure why.
The worst thing I ever did with my bi's was inject 6 shots of 3mls each of P&P into each one - all in one sitting. Hurt like a bastard and broke a capilary causing a nasty bruise on one arm. The next week I did the same thing only added 4 shots of 3mls each to the tri's too. So - one full bottle of P&P in the arms in 7 days time.
1 1/2 cc was the max ever done. But 1 cc is better, unless you have 17-18 inchers. Also one can shoot more if going in deep (and i mean in the bi's, hehehe).