But just for the sake of HR... cutting potent drugs with inert powders is not safe at all. Without proper binders, you end up with hot spots, the powders will not mix totally evenly. With potent opioids, this can easily lead to overdosing. It's much safer to use liquid measurement (volumetric dosing). Dissolve it into a known quantity of water or water/alcohol solution, and dose with an oral syringe. Say, 5 grams into 1 liter, and then 1mL = 5mg. Something like that.
Also, don't ever assume a vendor sends you the right amount. I have received double what I ordered before. It is often not right on and can vary a decent bit.