86TpiTransAm

Currently I'm running 24# injectors and the injector constant in the chip I'm using is set to whatever the stock 350 chip was. Since I don't have the equipment to burn my own chip and change the injector constant in the chip, what's the "ideal" place to start with my fuel pressure? I'm running 42psi right now. When I first installed this engine with the 24# injectors I was using the stock 305 chip and running 36psi and still running slightly rich but getting 20mpg. I just recently installed this new chip and I'm trying to figure out how low I should set my fuel pressure as to not run too rich. Any help would be appreciated.

(And before anyone goes and type it, I already know that I "should" buy the equipment and burn my own chips. That's not a realistic option for me at this point in time due to various reasons.)