Here is an image of my 35 hex. I plan to add more rocks to it... but I am a very bad artist, and I cant figure out what I want. Is there an artist out there willing to give me some ideas? hahah. I want plenty of room for corals, as well as some places for my fish to swim through.
A couple of thoughts: Don't sweat the rockscape. They are easy to change in new tanks. I look to have as much horizontal surface as possible to mount corals (many don't do well on vertical surfaces in aquariums with artificial light). I drill holes in my rock so frag plug stems fit in easily. Arches and caves are OK, just don't waste a lot of room for features that coral will struggle on.
It is going to be hard to offer any suggestions without seeing the extra rock. You will be surprised at how easily it will come together when you get some height in there and you start playing with the extra rock.
When I first setup my current tank I thought I was happy with my rock scape but after a bit I was looking at ways to make it look better, to make sure I had plenty of room for coral growth and for the fish to swim around. Don't sweat it too much put the rock in and if you don't like it you can move it around or take it out later.