Best way to clean the gas tank and main fuel line?

Yes, I'll do some shopping for tanks and lines. I already changed the fuel pump for a new Advance Auto Parts one. Wasn't going to trust the old one to not leak gas into the oil.

But the fuel sending unit, aren't the rheostats wound wrong to make the gauge at least factory level accurate? Best source for a fuel pickup assembly, gas tank, and the sealing ring for the filler tube? I need that too. Manufacturers to get or to avoid? I see lots of cheap stuff on amazon.