One thing I would do differently the next time is:
Build the structure in several pieces.
First, one large piece is HEAVY!! Trying to maneuver one single large piece into the tank can be a serious challenge. This is especially true when you have larger tanks that require more elaborate designs. I had a NSA scape piece break while lowering it into my 180. I was fortunate that the bottom glass did not break, but the experience led me to abandon the NSA design on that tank.
Second, When your tank is new, and you get algae outbreaks, it is FAR easier to clean off if you can remove the rocks in several chunks rather than one single huge mass. I have a HUGE algae bloom in my 55 right now. Fortunately most of my coral frags are not glued in place so I was able to move them off the rocks and remove the pieces that I actually could (meaning the pieces from the broken design from the 180 that got repurposed) and scrub off the algae.