Here is another gas tank idea. I bought a Gen5 Camaro pump with the basket and welded the top of GTO tank into a new A-Body tank.
The GM pump works like a surge tank in that it has a basket that surrounds the pump and a suction nozzle that fills the basket. In theory, shouldn't have any issues with slosh even at almost empty as the suction pump side of the setup keeps the basket overflowing with fuel.
Only downside I see is that I lost a little fuel capacity.
And it is untested as I still haven't installed it and used it. I am working on my G3 swap finally so maybe next summer?