DazedPete, while you personally may or may not have needed to start off with only 2 drops, it's not a bad choice after your experience!! Some have reported that using only one drop of a tincture has set off a herx.
Kate, yes, I would suggest using only a half dose. I made it with only 1/2 the amount of herb - so 1.5 grams of Houttuynia to 3 cups of water, and drink 1 cup 3 times a day. I would suggest that you use that amount for at least 1 - 2 weeks, before trying to raise it any.
If you begin herxing, you won't want to raise the amount until you quite herxing of course! And then raise your dose slowly. You don't want to go from 1/2 of a dose to a full dose overnight.
No one knows when a person will start to herx or if they even will herx, but the person herxing surely knows when it starts - and at that point you should raise the amount that you are detoxing until the herxing slows and your symptoms begin to settle back down.
I hope I've been able to answer your questions, Kate - I'm being distracted by my 2 yr old grandson!