Good to hear - tho' not for the worms i suppose :-)
Am guessing you mean 20 drops 35%?
I use around 5 teaspoons 3% in 0.5 litre. I think that is around the limit - there is certainly a more pressing sensation after 15-20 mins than otherwise.
And you are right about the anærobic thing. It is surprising how many posts talk about the need for (a lot of) probiotics afterwards.
This is why h202 seems so good for other things. From experience it makes an excellent toothpaste/body odour eliminator (that works for about a day and is fantastic)/mouthwash/skin care generally etc.
Also can be taken orally, though have not really tried yet.