[briHass]

Eyeballing RCs is always a bad idea, but if you don't have a scale, a much better way is to dissolve it in a liquid, at a 'known' concentration, and measure that. Alcohol (vodka) usually works well for most stuff at 1mg/ml. That makes it easy to measure with a baby oral syringe or one of the plastic 5ml cups that comes with cough syrup. The vodka also prevents mold/bacteria growth in the solution if it sits for months.

Even with a scale, this is a better method for low mg dosing RCs. Unless you spend thousands on lab grade equipment, Amazon scales can't measure a few mg accurately, even if they claim that.