Hmmm, I think you have a point. I've heard and read of that rule of thirds in a couple aquascaping papers and threads I've looked through. For some reason it's harder to pull off in person, lol.
I am a little disappointed in the acrylic rods though. They're much softer and pliable than I thought they'd be. I used 1/2" rod, but even the pillar tended to want to sag to one side at the top, even though the rod ran basically straight through it. I had to epoxy and shim quite a few of the larger pieces for it to stand straight and be solid. The arch piece absolutely will not stand on it's own and needs to be supported on the end, even though I built it on a large platform foot that could take the off centre weight. I didn't take the time with it though, to fill in the cracks between the larger pieces because I could tell right away I wasn't going to like it, but wanted to get the basic structure in the tank to see it. It's not what I had envisioned.
You are absolutely correct in describing it as a pop-corn necklace. The base is definitely too small, but I already seem to have more rock in there than I wanted. Damn, maybe I need a bigger tank.....the wife would kill me
So, I need to reconsider the arch. I'll try and take a FTS, print it and divide it up like you said. Then see what I can do to re-arrange those pieces.