I have had the hydor rotating tip thing (lol sorry) for months, and it works really well for me. Actually I had 2, one on either side. Anyway, my new plan is to have the hydor tip on my return (from the sump) right in the middle of the back-topish of the tank, then have 2 koralias in either top-back corner both facing towards the center of the tank. This way (in theory), the rotating head will disturb the flow of the 2 koralias as it spins on it's axis. Also, with the rotating head positioned this way, it will agitate the surface on every rotation too.
I donno if it will work, but it's worth a shot. Maybe you could consider something similar, with more or less of each product.