I use two inexpensive scales ($30-ish). I have a plug-in National Metallic and the newest Hornady battery version.
The National stays on, without a 60 time-out, so it is helpful.
I pour into the Hornady scale, then pour into the National. If they agree, I pour into the case.
If they do not agree, I adjust a grain or two until they agree. If they are disagree by 0.2 grain I recalibrate.
PS: the National Metallic can be agravating at times because it can take several seconds before it settles down to its final reading. The Hornady battery scale is quicker, seemingly instantaneous.
When these are working well, I will find that one may be consistently "heavy" and one consistently "light" but they will agree on one or two grains between them. That is, by adding a grain to the "light" scale, or taking one off the "heavy" scale both will agree on an exact 0.1 grain.
Sometimes I've used a balance beam as the second scale, but I find that two electronic scales are faster.
I also use two chronographs. Many times one or the other will register a duplicate velocity from shot to shot, so my charge weights are obviously tight. (Yes, the two chronographs will often be 5-15 fps different, that's why I use two and average all the readings.)