Inline Power Steering Pressure Regulator

You could do a poor man's pressure reducer by plumbing in a bypass line with a restrictor in it, 80% goes to gear 20% gets returned to pump.

Only thing I can think of about a pressure regulator is it might cause the pump to produce max pressure against the regulator all the time.

As is the only time there is significant pressure in the lines is if you are turning.

It has been a long time since I had hydrolics in school but that's how I remember it.