AndrewHow about a bespoke swirl pot with two LP inlets, one HP outlet, one HP return, and two tank returns with solenoid valves in series with LP pumps.
Switching one either pump will open the outlet back to its own tank.
Or put both on and vent back to both tanks if the flow will split evenly.
That would work but when you want fuel flow you have to energise the solenoid
With a Pollack it is only energised momentarily when it changes from one tank to the other. Brilliant idea but the plastic bits lets it down