Proportioning valve / rear brake problems

AJ's observations that the F and R ports from the MC were reversed is correct. In the pix above, the rear port form the MC should go to the top front port on the combo valve, and the front port on the MC should go to the top rear port on the combo valve. Here is the Wilwood link that has the info:
http://www.wilwood.com/MasterCylinders/MasterCylinderValves.aspx
Go to this link and see the 2nd part down the page, and follow the link to the 'Proportioning Valve Drawing'.

And yes, this is a 'combo' valve, with both an adjustable proportioning section (the knob) and a system failure switch (the electrical connection).