external fuel pressure regulator

Running a WVO set up on 12 valve and with all my junk, valves, 100 micron pre mechanical lift pump screen etc., my fuel pressure drops down to 10 psi WOT. I thought about adding an external fuel pressure regulator on the return side set up for 50 psi. IS this possible? I would like to mount it after the injector drip return line that used to go into the stock fuel filter but now Ts into the return line off the injection pump. I am worried that the pressure added after the T would cause problems. Any suggestions?

Pressure regulator after the injection pump works fine but I think your problem is the lift pump and filters they don't flow enough.

I think I am going to go with an electric FASS or similar pump and use it as a pusher pumper before the mechanical lift pump on the trunk.