[decodeddiesel]

Those are some very interesting specs you found. I can assume pressure, flow, and head are all directly related to the shape and design of the impeller and impeller housing. For example a large impeller with a large displacement housing would provide a good deal of "torque" and therefor flow, however less pressure than a a similar sized pimpeller and smaller housing. Just my theory on this... To answer your question I would aim more toward high pressure...this will make your droplets smaller, give them more of a chance to evaporate, increase the surface area of your water collumn, and theoretically reduce the noise of your bong.