Return line, can it be smaller than the feed line?

The return line can be smaller because it drops the pressure in the main line and it does so very easily. Guys that run a restricted orifice certainly don't have a 3/8 or a 5/16 restrictor. I use a hilborn jet can with no jet. Just the poppet and spring with shims to set the opening pressure. I use that at the back of the car so I wouldn't stall the pump and to knock the pressure down too. Up front I have a standard regulator. Didn't really see the need to have a second line with gas running the length of the car. Or having the main line charged with way more pressure than I needed.