Timing with a Procharger

I've been running a P-1SC ATI Procharger for about 2 years now. 410CI smallblock,8.3:1 cr quench dome pistons, 4150 carb, water injected, 11psi boost
So far I've been running about 28 degree's timing, just to be on the safe side. but I've been told with intercooling or water injection at these boost levels I can run pretty much full timing. This engine makes the best N/A power with about 36 degrees. I was thinking about bumping up the timing to 32 or 34 for an upcoming dyno run/drag run.
So my question for those of you have have experience with this, how much is too much timing for that combination Running on 92 octane? Race Gas?
Thanks.