Bob, you're saying that when using small eletrode(s) a significant volume of the gases being made is just water vapour? In my experimenting in the past I found that having a very small center(positive) electrode in a cylinder style unit produced the greatest volume of gases, but if 30% of it's water vapour that would be quite a deception. Btw, I made 3 new cylindrical electrolysis units yesterday using lye. Although the gas output was much lower than with the single unit with baking soda the bubble bang test

revealed much more(2x?) hydrogen/oxygen for the energy used.