I'm confused. PB is used to continue the circuit to another valve, Yes? If you pick up pressure after the pump and then take the out back to the closest place you just connected for input then PB is not even used. These are open center system, so they have fluid flowing all the time through the In and Out sports of the valve.
Whe I installed my FEL I connected to the 3 Pt valve & it was a mistake as it is too low in volume. To correct this I am going to "T" into the high pressure line coming out of the pump then go back to it from the out port. Had I done that initially I wouldn't have had to worry about the 3 Pt as it was already plumbed, but I was trying to use a valve to activate the float control on the 3 PT. I connected it in serial with the FEL valve. Everything works, but the FEL is slow because of the volume issue.