Those check weights look very cool.
I have shot thousands of rounds trying to optimize various rifles. In no case did any of my rifles make any difference at all due to 0.1 grain. In fact, the error due to that 0.1 grain was pretty negligible; I once calculated it. It is swamped by all the other errors and even more so, if you have a decent barrel.
I'm always somewhat surprised by people whohave so many problems with electronic scales. I have an RCBS Chargemaster, and its digital scale is alwasys perfect. I measured the little serving dish that comes with it, and wrote its weight in Sharpie on the bottom side. It is always within 0.1 grain every time.
I even bought a $29 MTM scale that I figured would be inaccurte -- but it always AGREES with the RCBS within 0.1 grain! It also weighs its serving dish accurately every time. Amazing.
One can also pick out a few bullets, weigh them carefully, and then keep them to check their scale at various grains -- from 22LR bullets all the way thru 200 grain .308's if need be.
Temperature changes the performance of my rifle and the bullet ballistcs way more than 0.1 grain, as far as I can tell.....