I am just curious, why the fixation on a beam balance scale? I have two electronic ones. The first was a Lyman Pocket Scale for about $35. It has .1gr resolution. Then, just for fun I bought a $16 one on Amazon that came with a calibration weight and several powder pan/funnels. It has .02gr resolution. What I really like about the electronic ones is the Tare function and the lack of any need to pour powder to/from a powder pan. I zero out the scale with a case or hull, drop the powder into that case/hull and put it back on the scale. You get the weight directly and no errors due to moving the powder to/from a pan. Unless you don't believe electronic ones aren't accurate, I don't see the advantage of a balance beam. Both my scales came with calibration weights and I have an independent set. The scales seem remarkably accurate.