I know you are not interested in electronic scales but I would like to add this. I have or have had three digital electronic scales. One is excellent (Dillon Dterminator) two not so much. Each having its own little nuanses but all three were extremely accurate. I have also owned two RCBS beam scales, the best one they sell and their cheapest...still have the 10.

a couple points -
Electronic scales are every bit as repeatable if used correctly and in accordance with directions.
They are faster in every way.
They will easily weigh objects of unknown nominal weight. Beams cannot.
I have a full set of check weights and have compared my beams with my electronics many times....its a wash.
In the 35 years I have been handloading I have had more problems with beam scales than I ever had with electronics.