Magnum EFI Return or Returnless? & Vacuum Regulator Question

Hello,
After doing some research I am not certain as to whether to run a Return or Returnless system on my stock EFI swap
-Donor: Magnum 1997 5.9 returnless system 50psi with stock pump
-Instead of stock pump I am using Tanks Inc, Tank, in tank pump, and adjustable regulator and adjusting to 50 psi

Called Tanks Inc and they said just mount regulator by fuel tank, no vacuum. But I am questioning this..... When I go to Aeromotive's website they state that a adjustable regulator should be placed alongside the fuel rail with a return line all the way back to tank.

What do you think is the best placement for regulator?

Also, the adjustable regulator has a vacuum port, should I being using this for optimum performance?

Thanks for your advice!
Rob