LS bypass fuel pressure regulator question

[weedoublewide]

Happy sunday!

Quick question,
I'm working on the fuel system on my swap need a little guidance.

Im working with the bypass fuel pressure regulator...Does it have to be plumbed to the top of the fuel tank or can it be tied back to the suction side of the fuel pump (external fuel pump).

I didn't know if it was purely vapors going back to the gas tank or liquids or a little bit of column a and a little bit of column b.

Thank you,

double.