I like the caves and it looks like you have some interesting pieces to work with... However from the pic it looks like the rocks are just barely holding into their place. Also if that is the case, it looks like you put the sand in before the rock. Due to water flow and sand dwelling creatures, the sand can move around a bit. If the rocks are not super solid, you could cause a rock slide (I learned this one the hard way)
When it comes down to the aquascape, it is all personal preference. If you are "iffy" about it now, you will be "iffy" about it later and will want to change it. It doesn't have to be perfect the first time as it will not be overgrown with corals immediately. Tweak it as you see fit until it is visually appealing to you. Think about placement of corals as well as swimming room for your fish. Sit down in the different chairs in the room and see how it looks from different angles.
If you want my personal preference and opinion I truly believe that less is more when it comes to aquascape. Keep it simple and have lots of open space. Caves, islands, and pillars are great ways to create a structure that is perfect for corals while leaving the open space that will keep your fish happy.