I make mine fairly watery. 1/2 cup root to 3-4 cups water, knead 10 minutes, pour in container, another 1-2 cups water, knead 5 minutes, add to container, enjoy (or chill first). I figure I might as well do the first and second squeezings together, since any root I keep around, even for a day, starts to smell sour.
I don't know if it's true, but I have this feeling that the water saturates quickly, even with 1/2 cup to 4 cups root/water ratio. As in, kneading for an hour in the same bowl of water won't be any different than kneading for 5 minutes (other than losing more of the yellowy goodness to the side of the bowl, or your hand for that matter). That's why people seem to get something useful out of a second squeezing, no matter how long they kneaded the first time. And that's why I immediately switch to a second, clean bowl, to quickly get out what's left.
Of course my preparation methods, just like everyone elses, were formed randomly and coincidentally with 0 scientific backing. It's a shame with all the studies done on all the health benefits of kava, their is no decent quantifiable data on which prep methods extract the most efficiently...