Hy Fourbrads, you should install the residual pressure valves as close as practical to the master cylinder. I do not believe there is any residual pressure function built into the proportioning valve. Do you know if your proportioning valve was used in a disc/drum or drum/drum application? The early drum/drum dual brake master cylinder systems didn't actually use a proportioning valve, what they used was more or less a manifold with a switch in the middle to warn the driver of a pressure differential between the two circuits, hope that helps.
