I think the towers are a good idea. If your planning on adding a fair amount of corals in the future I would also recommend drilling holes in the sides of the rock going up the tower so you have the ability to peg corals on the side. In my opinion when you have corals growing off the sided of rocks that are in that type of shape it gives it a real nice natural look. It can be difficult to mount corals on vertical rocks like that if you haven’t drilled holes for pegging. Watch the video on reefvideos.com to see how to do it if your unfamiliar with the pegging technique.