I think you're trying to solve one problem (poor idle on inverted four stroke) with another (fuel pump). Here's what I know:
The Perry PV30 is a pressure regulated pump. The adjustment screw backs-up a spring that controls the pumping diaphragm (I'm unclear as to exactly how the pressure/volume control works). Turning the screw in (clockwise) increases pressure. The plumbing that you used is correct. Unfortunately, if your tank is higher than your carb, I don't believe the pump will have any effect on siphoning.

Getting an inverted four stroke to idle well is a challenge. I would lower the tank to start with. Try an O.S. 'F' plug. As a last resort, you can try an onboard glow igniter that switches on at idle.

Good luck.