I think a dead stock, virgin truck would run between 11-14psi.
If you're at around 19psi now you're getting there with your settings.
Adding nozzles, housing, timing, exhaust,airfilter etc will take you into the 25-28 range roughly.
Remember, all the boost you need is enough to burn the fuel your supplying, any more and your wasting time and effort, not to mention starting to generate higher drive pressures and EGT's.
Hope that helps.
Bob.