I use a Lyman dispenser/trickler, and I should have spent the money on an RCBS. The lyman does the job, just takes longer as it has a tendency to throw charges .1-.3 grains over.
That being said, if I am looking for 44.0gr, I'll set if for 43.8. The charge usually comes up at 43.9 or 44.0, if I am lucky. I'll lightly tap the tube to get to 44.0. I re-calibrate the scale every 10 charges. I double check all charges on a second scale.
I use only Varget powder, and the extruded stuff requires you to put a dampener on the end of the dispensing tube. The machine learns to relate speed and duration of rotation to X weight per X amount of time. The scale counts up as it is dispensing, then it beeps when it is finished and the scale resets. Even though it will say it stopped at 44.0 grains, after beeping and resetting it often says something like 44.1 or 44.2. No biggie, just throw that powder back in, and set the pan back. It automatically starts a new charge.