I don't have anything similar, but I'd start by aiming to hit a water level just so that it fires the last perc and no more. That'd be the ideal amount to use all of the percs and not get water in your mouth.
as long as the pipe is underwater your good.if i can recommend buying an ash catcher.keeps the bong cleaner a lot longer, or at least it just gets green without the black shit.allsoo its one extra filtration chamber