How would you run the return ??

Correct, I was envisioning something simple and basic for the bulkhead fitting. Here is the sort of sump I envisioned:

Competition Engineering 4040: Fuel Tank Sump Kit 11" L x 7-3/8" W x 3" H - JEGS

Except if you already have a welder and a saw, you can use a cake pan just as easily.
I’m with you, if you’re going to weld on the tank may as well put in a sump.

Never thought of a cake pan, going to keep that in the back of my brain:thankyou: