I think progress is being made with each try (at the expense of your hands) I've liked each version better than the first, and I think it all boils down to personal preference now. You will be the one staring at this setup for endless hours.
What you have in the third try seems to be similar to the first but better executed. Still a bit or a rock pile, but its hiding the center like you wanted and I see more flat spots for coral mounting and more holes/caves for fish. You also managed to give a lot of lagoon like variations in how close the rock gets to the front/back and side to side, which I think looks great.
What you have in the third try seems to be similar to the first but better executed. Still a bit or a rock pile, but its hiding the center like you wanted and I see more flat spots for coral mounting and more holes/caves for fish. You also managed to give a lot of lagoon like variations in how close the rock gets to the front/back and side to side, which I think looks great.