Help with a fuel system

Hey guys!

I was working on a fuel system for my dart today and came into some confusion in the process, I was hoping yall could help clear some things up for me. I have a carburetor with a single fuel inlet, and another fuel inlet/outlet that looks blocked. I was going to plumb a fuel return system like the one in the picture below, having two hookups to the inlet/outlet's of the carb. My question is how should i run a fuel return line from this carb? Should I use the one inlet or try to unblock the other, and use both? Or do I run a pressure regulator right before the inlet with one line going to the carb and the other back to the tank?

Thanks for the help guys!!!