Hawaiian varieties do not cause the nauseating feeling, I wish that I had some of my Hawaiian 'Awa (Kava) ready for sale but not yet, I hope to have some Hawaiian in the next few weeks. Also when i make my kava, I will try it slowly meaning I will try it over a few days, I will make my normal strength of kava, meaning my normal weight of kava and amount of water, I make my drink and then I will take one big gulp, then wait for about 5-10 min and go for another big gulp and wait 5-10 min and another big gulp, if you need it. This way you get to know the kava better and you can avoid the nauseating feeling sometimes by doing it that way. Aloha.
Chris