When I first start, I find the measure is more consistent if I throw about ten "practice" charges and tap the hopper itself between throws. I don't load any of the throws, but dump them back in the hopper. If your hopper is a tall one, a baffle which keeps the weight of the tall column of powder off the cylinder helps too.
I'm with the other guys - a consistent +/- 0.1 grains is good enough, unless you're near the upper limit of safe charge or maybe benchrest, which I've never done. There are so many other variables; e.g., neck tension, crimp, case capacity, barrel heat, leading - that a tenth grain is pretty much moot for most shooting. Do watch out for a slow upward creep - I weigh one every ten to twenty throws to be sure my measure is stable. Historical experience with your measure and powder type will let you adjust that frequency as needed.