What's the best way to prepare the powder?
The best way is traditional prep.
Add the preferred amount of Kava into strainer bag (75 micron nylon mesh is what I use) over a large bowl or bucket.
Add water to the bowl (warm water is what I prefer) and massage the Kava in the water while giving it a good squeeze here and there.
The massaging and squeezing process should take no more than 5min.
Give it one last good squeeze and Bula!