Glad to have you on board, I see by the post count you might be new to our forum and we enjoy the new perspective. There are many of those tanks on site and someone will surely chime in directly with their powerhead count, but in the meantime I can tell you I set up a friend's oceanic biocube at 24g's with only one powerhead, the stock one worked fine for the amount of rock we used. If someone plans on stocking heavy with live rock this can make pockets of lower circulation, so one might consider using multiple smaller pumps or those rotating pump heads or a single large pump with an outflow bar to minimize those gaps, I always used the technique of stirring up the sand a bit in a questionable spot and see where the detritus floats off to (or if it fell back down due to no flo). Here's the pump we used: http://www.marinedepot.com/aquarium_pow ... sp?CartId=
as long as you establish high volume flow with low velocity, it's very difficult to overdo it
the problem is that the rs wavemasters aren't really designed for any other than narrow spout powerheads (low volume high velocity), like the maxijets-the immediate start/stop messes up impellers and magnets, as opposed to a 'soft start' wavemaker
you're better off getting seios, korallias, etc as the main constant flow makers, and using mebbe one reg powerhead on the wavemaster for pulsing/randomizing the currents
I've got a SCWD hooked up to my Rio 2100 Plus and I love it. The pump runs from my refugium to a jet on either side of the tank. The current alternates every 16 seconds between the jets, and they are pointed at the surface of the water.
For LPS's I would go with no less than 20x turnover rate. SPS's can do 40x.