One of the arts of mastering kava, I've learned, is understanding the logic and math and science and art of multiple washes.
One thing I learned? My first shell, with 4 TBS of waka is great, but what is even better is the second wash, the 4 TBS of makas from the first wash, done up again but with another new TBS of waka added. That second one is better than the first, and it's even better if I chase it by sipping 2 TBS of KWK concentrate in a glass with water and ice. My wife claims she can take the makas from that and do a third wash that is really nice and mellow, like doing 2 - 3 TBS of lawena.
For a day long session, I'll do 5 shells like this:
1. 4 TBS waka
2. The makas from 1 plus a new TBS
3. A new 4 TBS of waka
4. The makas from 3 plus a new TBS
5. All of the combined makas from 2 and 4
The aim of this was to make each shell have roughly the same effect and power on me, as if I were having 4 new TBS with each shell, which I had been doing, at considerable expense.
In effect I get 20 TBS of kava goodness out of 10 TBS of kava. Once I learned these tricks I saved a lot of money, well, half my money.