Thanks, Dave, that looks real interesting.

Today I had a long phone conversation with the engineer who designed this nozzle package.  The most important thing I learned was how little I know about the use of regulators on a nozzle package.  Once I specify the gpm, that it what flows through the nozzles, regardless of the system pressure.  Finding the right balance on the pump curve can be a little tricky when you don't have a pump curve.  Trial and error varying of the discharge to arrive at the desired pressure should give us a flow rate if we had a flow meter.  Now I need to find a good cheap source for an 8" McCrometer.

Thanks again for the link/advice.  Gary