Today I payed around some more. Did some more flash back explosions and eventually my poor man's bubbler design cracked on the bottom side. That is because the plumbing plastic is not flexible enough.
I also attached the HHO torch to the electrolyzer, but I was surprised to see that the flame is almost 2x smaller than with my previous design. That is weird, because this design should be superior to that I had before. My first electrolyzer had also some neutral plates, the current design does not. Previous design ran on 27V 20A, this one runs on 12V 20A. If I press off the torch tip with my thumb and let the pressure to build up for a while an then ignite the hho, I get a large beautiful flame for some seconds, but then as the pressure goes down, the flame becomes shorter. What could be the problem?