Hi Najman,
That looks like a nice drycell to me!
Well done.
I hope it will work out for you with the one hole concept.
For me it wasnt so good, because the tapwater produces lots of scum.
For that reason i turned the concept to be a closed waterflow circuit with a pump.
So, at the end, i had to use the lower hole for water input and i used the gas output hole also as water output.
At the end, i ended up with a waterreservoir, as you have seen. Thats the gray bubbler. It has a double function.
You will get gas production with a 0.9mm gasket.
If you want, i can send you some of my 0.5mm material.
"its a nasty piece of work to cut all those gaskets....."
br
Steve