Hope I didn't sway you, I didn't recommend a hi pressure, I stated that's what I use. You do you. I think a hi pressure solves a lot of flow issues, and keeps fuel circulating. It also came with fuel tank, and as I planned to one day go EFI, is my work around more than trying to solve a carb flow issue. But it works great. Even a lower pressure carter pump, can use a bypass regulator, end with the same result.
Aeromotive is the bypass regulator I used, not cheap, not cheap because it works. I also used two aeromotive fuel pressure gauges to verify 4.5 psi at pump and 4.5 at carb. Those are permanently mounted. One by carb leaked it's oil bath out and I chased a supposed engine leak for months, it was the gauge leaking. It doesn't need oil to work.
Dual tanks, when I had them, I ran outlet of small to big one, when big one ran low, I pumped it into big one. The under seat valve proved leaky no matter what I did. There is an electric valve used on bigger trucks, I found that to cumbersome with something like 6 hose lines, none of them the size I wanted meaning adapters totaling 18 fitting points and leak potentials.
Under hood temps, irrelevant IMO, and I live in or lived in Phoenix, it's hot, 200-300 degrees. If your carb has a spacer between it and intake, that should insulate it enough. There are aluminum plates you can buy as well. I just used a phenolic 1/2 spacer between carb and intake. Also needed it to get throttle linkage to not rub on intake. I have 2 inch body lift so no hood clearance issues.
