Quote Originally Posted by kz1000r
I use 1/8 teaspoon of powdered (coffee grinder) bud and it is plenty for me, i use about 1/4 oz per month and i use it every day.
Personally, I wouldn't recommend powdered herb for any vape. Powder gets too easily blown through screens in the case of bag vapes (I've experienced it with my herbalAire) and sucked up into whips. Ideally, the particles should be larger than the holes in whatever screen you're using. Granted it's difficult to achieve if you're grinding dry herb. Also, the smaller the particles, the more closely packed they'll be and air flow can be restricted, making the process more inefficient.