Im also voting for the Italian spiral burner, thats the one Im using too.
My Italian has a power of 9.6KW, thats far enough to boil a 60 liter batch.
Im using also another mighty burner, one that consumes 12.6KW, but I gotta say, the more gas you are blowing in, the more gas youre losing into the environments. There is only a limited heat capacity, depends on the surface of the pot, you may get into the liqid. In another words, it doesnt really matters wether Im using the 9.6KW burner or the 12.6KW burner, the time it needs to get to the boil is almost the same, but with the bigger burner youll certainly lose more gas/energy.
Cheers :icon_cheers: