I finally got round to fabricating a box to hold the 6-port valves. I wanted to centralize the valves and protect them from heat and water. I'll mount it under the bed behind the cross member that holds the rear of the cab. Ordinarily I would not use worm clamps, but at most we are talking 10 psi and it makes servicing the valves straightforward.
There are 6 inputs (feed and return for each of 3 fuel tanks) and two outputs.
I have to figure out how to do the electrical in/out and sort out the wiring itself. I'll fit a heat shield on the bottom of the box since the exhaust will be directly below it. This set up will allow me to cycle between 3 fuel tanks by switching supply lines, return lines, and fuel level sender wire.
I've got the new pumps and hangers for the saddle tanks. Wiring is what remains...and removing the bed to get to it all.