Quote Originally Posted by ricardo12458 View Post
...The only problem is......a lot of the units are denominated in grains.....don't think there is a modern scale that measures so accurately....

-R
The conversion from grains to grams is straightforward, either by formula or table. At that point, it is the exact same issue as any other small quantity measurement. You make a solution using enough of the chemical that your scale can accurately weigh it, and then use a volume of the solution that delivers the original quantity specified in the recipe. This is the reason to use drops or mls of 1% or 10% solutions.