What do you mean by "fuel tank transfer pump"?
Do you have multiple tanks and pump from one to another?
Yes, instead of using a fuel tank selector valve. Just turn on a pump to move fuel from the rear tank to the front, even when driving down the road.
In theory, you could use any tank from any vehicle that way, as long as it has a "carburetor" type sending unit pickup, like IDIs have. In other words, a tank without an internal fuel pump like on fuel injected vehicles. It would be a storage tank for transfering from, no fuel level gauge needed.
It's a roundabout way of doing it I suppose, but for now it's way cheaper than messing with a failure-prone fuel tank selector valve.
My front tank's gauge is pretty accurate, so I can judge how much I add to it from the rear tank. From half tank, I should be able to get it back to full once, twice if the shower head is still attached. If it's not, it would stop filling at about 3/4 tank level on the second transfer.
Either way, it gives at least 13 gallons more capacity without the screwy FSV. 17-18 if the shower head is there.