What fuel system to use

How much boost? The pump needs to deliver normal carb pressure + pressure equal to the boost + some extra for margin or Factor of Safety. If the boost is only going to be a couple psi, then a 10 psi pump might work. I'm guessing more like 10 psi worth of boost, so adding that to carb fuel pressure + some margin I think that you're looking at 20 psi minimum. Pishta's trick of referencing the mech pump diaphragm to boost will raise the fuel pressure with boost, but I prefer having the whole supply line under pressure for vapor lock considerations so I think in terms of EFI pumps mounted at or near the fuel tank.

A 3/8" supply line will feed 90%+ of streetable engine combos, boosted or not. I ran a 3/8 supply and used the existing 5/16 supply for the return.