I don't think this is the same valve as the RWAL system used. I think the proportioning valve for that is somehow connected up with the master cylinder according to our Chilton. We don't have it, so I haven't studied it, though.
On the topic of our problem, we found a '98 at a wrecking yard and they sold us the one from that vehicle for $50. Put it in last night and "voila", we now get fluid where and when we should! Got the right spring kit for the rear drums this time, too. The last time we replaced the hardware, we suspect we were given the wrong kit, probably the one for a 2dr.
Anyways, thanks a lot for all the help, Zukifolks. Now to go take the old valve apart just for the fun of it to see what was up!