Ahh, good times when I made one of these bad boys with EE2. But this is quite a bit more complicated, if at half the speed. I wonder, even though it's much more polished and smaller, if it's worth the extra time. When you say 18x4 blocks, do you mean 18x18 4 deep? If so, HV arrays can be created in the same space you have here with normal tubing and a lot more basic, though it would take more space, it would stay within the 4 chunk limit you seem to have yourself. Now, condensing this two blocks, and having it go down a few more would make this build that much more impressive.
I am not saying this isn't impressive in any way, and I am not saying I could do better (cause I sure can't). Just some tips to try out next time, or maybe a modification. Your goal should be 1 chunk, because with 1 chunk, you're able to have a small area loaded, instead of four. If one of those areas are not loaded, problems may occur.