Here's another thought/question (I know Im full of them). Would you be able to use a combination valve (porportioning valve/metering valve/differential pressure switch) with a drum brake system. It seems logical that I could, seeing that the porportioning valve would regulate the rear pressure, the metering valve would hold off the fronts until the rear starts braking (I know this is only for vehicles with front disc's) and the pressure switch would just be an extra as I could mount a warning light in the cab.
Im planning on putting disc brakes on the front so this will have to be plumbed in eventually. And it will only be in this configuration driving around my yard as it will have front disc's by time it hits the road.
What do you think?