My bubble cap alone has a Ø 4.5" with 14 risers, 10 x 3/4" and 4 x 5/8". I saw pictures where there are only six bubble caps and one down comer on that Ø 4" surface... Theoretically, I should have a higher output, providing the gas burner can follow as well as the down comers.
I saw very short down comers, I'll have longer ones to enable the separation of vapour from the liquid in the aerated liquid (bubbles/froth if any) in the down comer. I'd like to have a reduction Ø 1" to Ø 3/4" (ID) at the entrance of the down comers but the copper fittings I can find are made of red brass, although they claim it's red copper ! Furthermore, I may try to enlarge that opening a little, or cut some slots...
Thank you for your appreciation and kind words !