In my opinion your scape needs to have multiple levels where you can attach the corals to support different lighting requirements (assuming mixed reef). Also keep in mind that your finished scape is not what you will see long term. The coral itself is the highlight of your tank, not the rock. Give yourself room both from the top of the tank and around the edges for coral to grow into and fill in. You may not like it as much the first year but you will like it better long term.
I also recommend making sure everything is secure. Put in the rock before you add sand so it is resting on the bottom. If possible, bond the rock together using putty, glue, or other methods so it can't shift. Otherwise, you may limit what livestock you can add in the future.
