I bought the acrylic rods, and enough epoxy to glue my car into the garage with these great plans of making super awesome overhangs and piers. So I start drilling rocks, and inserting rods. I do this for 3 hours before I get frustrated, pull all the rods out, and put the rock back in the tank in a pile. I found it very difficult to get the rocks to line up exactly the way I wanted to because the holes you drill have to line up perfectly, which is quite tough. A week later I buy a bunch of black zip ties, and give it another go. I used a masonry bit to drill holes just like the acrylic rods, but they holes don't have to line up perfectly for you to tie them together. Waaaaaaaaaaaaaay easier! I was able to make the structures I wanted (although I have decided I don't like them anymore, but that's a different story lol). Four months later the zip ties were overgrown with coralline, and you can't see them unless you're looking for them.
This is what I ended up with just using zip ties (no epoxy):
