from what i have read, if your going to add it in.. i would add it now while its cycling as if you add it later its going to mess with the cycle.
tony if your going to add more rocks, look at whisks thread and see how his rocks are setup.. we may need to break some of your bigger peaices with a hammer (like i did with my tank) and that way you can set it up like his.. i think it looks really cool like taht with the sides filled and then the middle of it o pen like that.. just a matter of preference.. however you like it.. check his out.