Magnum EFI Return or Returnless? & Vacuum Regulator Question

Got it. Thanks. Does the return line from engine bay back to fuel tank have to be EFI hose, or can it be standard fuel hose?

Racing regs are no more than a certain amount of rubber hose in the entire line, and it isn't much.
Maybe consider nylon 12 EFI line or steel/aluminum if wanting to pass regs.
I ran 3/8 nylon 12 for the feed and return both, though I have no intention of racing it.