Try using a baffle in side the powder reservoir to maintain a constant head over the measuring cylinder. You can make one easily out of cardboard. The best way to get charge consistency.

I have two Lyman 55 measures. I set them by throwing five charges and dividing by five. i.e. I if I want a five grain charge, I set my powder scale at 25 grains, then throw five charges. Adjust the measure until you throw five charges which weighs 25 grains.