It actually can make a difference. It's a Pascal's law sort of thing. Still catching up on the thread, but I gotta make a note here. You shouldn't have a proportioning valve in an all drum brake system. You will only have a metering block that will sense a pressure differential if you develop a leak.
Have you grabbed your trusty FSM, sat down with a beer and just double checked everything? How does the fluid flow when you bleed the brakes?
Sorry if those questions have been asked. I am trying to catch up here.
