i'm not sure, but i think if you put a 12mm head with those dinky small pee hole nozzles, you'll make some decent power. the larger nozzles are good because they usually have more orifices to spray the fuel, and achieve a better atomization. sorry for your loss on those great nozzles
lord have mercy on the soul who has taken these, if you ever got your hands on him...
messing with the fuel screw will help, but theres a fine line between more power and just a bunch of smoke
i think going too wild will start messing with the internal pressure of the pump too.. but could be wrong.