I could be wrong about this but I am sure that other members will correct me.
The Fuel comes from the tank to the New fuel pump then out the Pressure side of the fuel pump and then through your tunnel and to the pressurized side of the fuel rail system.
After the fuel rail is the fuel pressurized then the rail continues to the regulator. Whatever excess fuel pressure that is above the required amount per the regulator is then discharged into the return fuel line back through the tunnel and into the fuel tank.
Think of the return fuel line as a pressure dump for excess psi so as to not over load the fuel circuit.
I am in the process of relocating my oem fuel pump to the front and simultaneously switching over to a 2 port cylinder style fuel pump from the dreaded 3 port pump.
I will be using you as my gineou pig I guess.
Let me know if it works..
If I don't hear from you I will assume that you died in a firey 914 fuel pump mishap and then I will have to hit the books again.
Pete