Just don't open the valves all the way if the pressure is too high, and turn off some of the lines when the pressure gets too low. Downhill sections will of course be the one's to blow out or over-pressure so remember that when opening their valves. I say wing it, it is not like you are dealing with 2 inch water lines and hundreds of pounds of pressure. Just observe how the system works at different pressures and open the valves accordingly so it works right.