Re: How critical is measuring powder to .01 grains
First, let's not forget that a grain isn't just a grain, nor is a tenth of a grain just a tenth of a grain; it's a percentage of the total charge weight. A tenth of a grain can be a fairly substantial amount of powder if you're loading a 25 ACP or even a 22 Hornet. It is absolutely insignificant if you're loading a 30/378 Weatherby. There, even a full grain of powder probably won't show nearly as much influence on pressures as that tenth would in the Hornet.
Match the percentage to the case being loaded, and you'll save yourself a lot of frustration down the road.