Built Turbo GSR Fuel Pressure

I have a 1996 GSR w/ a 1995 OBD-1 B18C Motor in it. The car is running an LS Tranny w/ a Quaife LSD. The bottom end is fully sleeved and decked and has a aftermarket crank, rods, pistons etc. The valvetrain is stock. I am told by the guy that built my motor that it will hold 22 psi w/ proper fuel. I also have RC 440 cc injectors, enlarged throttlebody and an Skunk2 Intake manifold, T3/T4 AR .50 w/ largest Greddy intercooler they make, and an HKS Wastegate that I was also told is not made anymore and that it is twice the size of any wastegate currently sold ( some guy offered me $450.00 for it the other day, lol ), and an Apex S-AFC no computer. I am also told the car has an upgraded fuel pump. I just ordered the AEM Fuel Rail & Adjustable Regulator. The Car is currently running an half bar of boost, can I run 1 Bar with my current setup or is that not an good idea, I do not know how much fuel pressure I should have on my car once I put the regulator on at idle and WOT. Can anybody help me that has any knowledge in this area. Also I have a feeling that my injectors are too small. Should I upgrade to 550 or 600 plus even if I never PLAN to go over 1 Bar.

Thank You,

Benjamin P. DiSabatino IV