as usually i havn't found dremel diamond cutting disk, i will try with a diamond mill for dentist, maybe blocked on lathe.
I made a sort of pattern from steel on lathe, work is not so nice to see, but size is good, I really don't know if this template will be good for modelling the chamber or not, but for sure i'll try! I think I will try your advice of modified plyers, and then melt glass on glass to reach some thickness
The others parts are new clamps for tungsten and the small one is the central point of earth (GND, don't know if it's the right name) in brass, drilled and threaded , i need some inox grains. hope tomorrow with polished tube plate i will start welding circuit and power supply... i'm curious to see the flame