need some advice, running 3/8" fuel line, how to run, what to use

I have used braided stainless steel AN-6 hose on a few cars for the complete fuel system. Get the good stuff (Earl's, Russell, Aeroquip) and it will not rot. The stuff they are making now is compatible with today's fuels.

Agree. Even the PTFE stuff isn’t too expensive anymore.

AN Hose - PTFE Lined - Bio-Fuel Fluid Type

The fittings can be a PIA. Just get the right tool.