17 more done, leaving 193 left to go. I probably won't need many more triplets with 12" 4-conductor sections. They're quite long and way more than I need for most of the pixels.
I've made 60 holes (half of what I need) in the section I have (mostly) constructed. One per pixel, each slightly larger than 1/4". The largest drill bit I have is 1/4" and one LED head fits through just fine, but I need to feed the other two LED heads through as well, the last of which also has 4 wires to contend with as well. A few swipes with a circular file slots the hole well enough to fit everything fine.
That is all. Nothing major, just more busywork.