Dual Tanks/Fuel Line Size Question

[52Chevy4Me]

First time poster, but have been getting a lot of great information from the forum for a long time.

I'm adding dual tanks on my '85 K20 build. I'm trying to stay true to factory by keeping the fuel return line as 1/4", yet all the aftermarket selector valves that I have looked at are 5/16" return. Were factory selector valves built for 1/4" return lines?

Any help on how to plumb it is greatly appreciated.