I have anxiety too and I'll just share my experience. I love GHK, best seller hands down. Moi makes me anxious though. My go to is Mahakea. All kavas make it harder for me to sleep if taken within 2 hours of trying to sleep. Better to take 4+ hours before sleep and then once it starts wearing off that's when I get sleepy from it. Also, too much Moi can make me have rebound insomnia - where I wake up a few hours after falling asleep.
To reduce sides, stick to instant and take the smallest dose that gives desired effect on an empty stomach. You can also eat a little something that combines carbs/protein/fat 30 mins later to increase the anxiety reducing effects. I've had good success with fried chicken and pizza - but only with a small portion.
Overall, I find micronized is the best way to go for me. There's a slightly higher chance of sides than with instant, but it's a better value. Try 2 teaspoons to start.
Every 30 minutes? I could never afford that!!! LOL! Thankfully I seem to be getting effects from even 1/2 a teaspoon so I think 1 teaspoon will work for me but I don't know how often to repeat throughout the day to keep my nerves settled down.