The take-too-big-and-trim strategy is not comfortable for me to use. I know a person working at a pharmacy and I can ask him to weigh something for me, but there’s no way I’ll be able to borrow a scale to run the iterative process. So I sought a scale that would allow me to calibrate with arbitrary weight. After reading instructions for about 20 cheap scales I found one that has this feature:

It’s called DP-01 and costs under $11 shipped. I failed to find any opinions about it though, I guess I’ll have to test my luck.