Yes, you'll need to regulate the fuel going into the fuel solenoid. The cheap holley regulator will work fine. http://www.holley.com/12-803.asp
Definately use a regulator and flow it properly before each pass. The yellowbullet guys like the $20 holley's. I think you are using an NOS plate and most of their stuff is 6psi but be sure to check. You telling me you don't know what PSi you've been spraying all this time? 1/4 psi adjustments make a difference in the tune.
i mean either 5psi or 14 psi the gas is still only going through a small ass hole on the plate? but i guess it does.
JACKO
if you use a small return line back to the cell with a standard holley jet installed it will help keep the pressure more consistent..