The top end Sartorius scales are excellent, but pricey. Super accurate - but probably way more than you need for reloading.
I use an A&D FX120i, and very happy with the 0.02 gn resolution. In milligram mode you gain a little more resolution, but you don’t need it for powder charge measurement (one kernel of powder reads 2-3 milligram).
The FX120i settles to the right nr very quickly because it uses force restoration technology. It is not just about scale resolution.
After much experimentation, i have come to the conclusion that a scale with 0.05 grain resolution is good enough (2 kernels of powder, about equivalent to 3-5 fps) - if you shoot at steel targets. An F- class or long range BR competitor might need a bit more.
There are other sources of variation that dominate your ES, like variable neck tension, slightly difference amounts of primer compound, a gradual rise in barrel temperature and progressive barrel fouling, faint carbon rings, etc.
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