When I first started drinking kava all, the only prep method I knew of was toss & wash, so that's what I did! It works, and it works well. But, and this is a big one. It can cause dermapothy so much faster than traditional prep. My skin....it didn't thank me ONE bit for that. More potent? Sure, but with a price. Now days I either consume instant kava, or go the distance and prep it with the whole "squeeze and knead" method. It was fun and effective when I started, but over time kava teaches YOU how to use it. This will most likely lead to consuming traditional prep, micronized, or instant. Most importantly, listen to your body. If it's groaning every time you drink unfiltered kava, then try the other methods.
Also you're about right on the money for proportions. Try the 4 tbsp with traditional prep and see how it treats you. 4 tbsp is about an ounce or 28 grams. I use about 6 to 6 1/2 tbsp and have been for about 3 or so years. Before that I was using closer to 70 grams which eventually ended up being too much.