Pantera EFI and pressure regulator

[Van B]

I was hoping Lance from Pantera might see this and chime in.

My dad is having a 55 Chevy built running a Wegner L92 with Pantera EFI using the GMPP carb manifold fitted with fuel rails. As supplied by Wegner the regulator is plumbed before the fuel rails with regard to flow (on the supply side). The guy who is building the car insists that the regulator must be plumbed after the fuel rails (on the return side).

I couldn't tell you which is right, but I seem to remember hearing of systems plumbed both ways.

Little help?