Considering your source and its been tested for very good quality an average would be 15-30g and for a strong dose is 40-60g a heavy dose is 60g-100g, and im just saying from what I heard mostly some say 30 is very good start and 40-50 is for elite users but I think the random and immediates are far to high so im doing 60g.

Erowids: 15g-100g is 300mg and usually getting something that you need to take 100g for 300mg is pretty uncommon in powder and if anything very poor quality. So if your powder is 15g/300mg or 40g/300mg you could be dosing at lowest 400mg/500mg and highest around the 1,000s in mgs but highly unlikely since 15/300mg is uncommon but not a rarirty, so you should start low maybe to tets your product but im doing 60g regardless.