I look for 760-780's top of third gear as a baseline. And work from there getting them down. If it runs 24 PSI at 760's.. you can try lowering the fuel amount to drop the O2's further. This can be done via the chip, fuel pressure regulator, or translator if you run an extender. At the same time adding timing will also make the car faster.
Watch for knock. If you get some that is steady.. add alcohol to get rid of it. Dont pay attention to false knock like that which is encountered when the transmission shifts for example.
Everyone has their limits as too how much boost you want to run, how much timing, how lean, etc... Set your goals and work to get it there.