Carb fuel pressure issues

Holley says the 750 fuel pressure should be set from 6.0 to 6.5.

Thanks! Read this last night set it at that today and adjusted bowls. Worked like a champ and then fuel pressure started to vary again and at one point I believe I sucked the bowl dry. Had to pull over and adjust it to get home. The fuel pressure is playing tag with me and therefore, the bowls are not staying consistent. I am parking the car and getting a electric pump and possibly doing that return line. Thank You