It's definitely going to be a reef. As far as rock placement I leaned a few of the larger pieces against glass and built off of that. I made sure to leave wide swimming and flow area however behind and between most of the rock work.
I'm going to add a closed loop soon running off of dart. After I have that in place I need to to add some baffles to my sump for a fuge. I have a 33 long for sump with external skimmer, so there's plenty of fuge space.