I think that there are a few things to keep in mind when setting up your rock. I have always had the best success by using the largest pieces of high quality rock as possible. I have done a bunch of tanks using small pieces and usually ended up with the traditional pile of rock rubble. My last 2 tanks ( 54 corner and 120xl ELOS) I used the largest rock I could afford and fit into the tank and felt like the results we the best I have ever had after 15 year of this. It also allowed for the most unique, functional, and healthiest (no flow dead spots).
The second thing I would keep in mind is your eye needs to be directed in the tank. There is a rule that some of the really great "aquascapres" talk about as well as people who deal with aesthetics on a daily basis called the Golden Triangle. 3 points of focus in the tank that you eye moves between. Just like a painting or photograph your eye needs to move throughout the tank, it needs to be moved from 1 area to the next, and never out of the "frame" so to speak.
Hope that helps