The reason for reducing the gas burner holes is that hydrogen burns so much hotter than LP/methane that when adapting a gas cooking burner, you need less holes if operating at the same regulated pressure and with a standard lp/methane jet and metering valve regulating gas flow. The stainless steel wool promotes mixing and as a catalytic surface helps reduce the flame temperatures and has the advantage of letting you see the flame. Sufficient air mixing is at the stainless steel wool, premixing just creates an explosive mix so is avoided. I found the information on the use of stainless steel wool somewhere on the web; I did not develop this myself, only experimented with it as an option for my off grid home. I thought that variable gas rate generation under modest pressure to avoid pumping and storage was possible by raising/lowering the scrap aluminum into the lye bath or by controlling lye-water pumping rate, spraying the lye over the scrap aluminum.
Various schemes have been proven for hydrogen generation via aluminum, including a water filled, aluminum wire feed against a rotating aluminum drum with electrical current applied to the wire. The drum speed and wire feed rate control the gas generation rate. One inventor used this successfully for an aluminum-hydrogen driven car.
Aluminum in lye water does NOT generate oxygen, which makes it an appealing hydrogen source. Just make sure that you let it run to purge any air in your generation tank- the first gas you get will have enough air in it to be explosive. An be prepared to deal with the rapidly heating lye water/aluminum solution...it will get very hot and will melt plastic unless you provide cooling. (You can imagine how I learned that lesson.)
The hydrogen car fantasy- that only water drips from the tailpipe, is only just that. The NOx problem is still there, when burning air. If you burned brown's gas (with oxygen, not air) then it would be true.