Also, if you have a pretty normal setup as far as injectors go, keep your fuel pressure at idle in the low to mid 40s. Turning that screw and lowering fuel pressure across the board is worse than making changes to the fuel table.

Ideally, set fuel pressure at idle to what your injectors are rated for, quite possibly 43.5 but I'm not sure on your exact ones. Then, be sure your Req Fuel value in megasquirt is correct. Then, leave reqfuel and the fuel pressure reg alone and worry about your fuel table.

Check AFR if you can (hopefully you have a wideband on this sort of setup, it is near-essential). There are other methods, but for the money you can't go wrong, especially on a motor you have some money tied up in.