1/2" Pickup and Return. How?

I used a step drill bit, a narrower one. It tends to leave a step pushed out on the back side of the hole when used on sheet metal. That aids in mechanically holding it. After the hole is sized for a slight interference fit with your 1/2" steel line, I silver solder the two parts together. Use real silver solder, not the cheap substitute available at hardware stores these days. I picked up mine from a welding supply store at a cost of about $50, including the liquid flux, a roll of real silver solder and an acid brush.

I pre-bend the tubes using a tubing bender and added a radius lip on the ends I added line to. They make tools to add the radiused ridge near the tip of the line. Those are available at Summit and other tool suppliers. The stick into the end of the tube and are rotated as you tighten them. This slowly extends several ball bearings outward making the radiused lip about 1/4" back from the end. It helps hold the line on.

I add a few inches of submersible rated fuel line to the return line and a second piece of tubing to allow the returning fuel to re-enter the tank down low, so as not to create a lot of bubbles when returning fuel to the tank.