The only thing to add from my original open loop Maf tuning is to check the LTFT's after installing the stock O2 sensor.
I set up a STFT+LTFT pid & insert this pid into the Maf Hz histogram. Then you can fine tune the fuel trims (up to ~7500 Hz), as the evap purge will be causing negative fuel trims. This is because in open loop, the evap purge valve stays closed.
Russ Kemp