These are the ones I ordered, they’re $39.80 for 100, with free shipping: http://www.aliexpress.com/item/12mm-100-node-lot-DC-5V-waterproof-IP68-Full-Color-addressable-WS2801-RGB-RGB-Pixel-Module/32322649250.html
They seem similar to the ones Adafruit carries: https://www.adafruit.com/product/322
They’re 8mm LEDs, sealed in a silicone sleeve. They say: “There are four flanges molded in so that you can ‘push’ them into a 12mm drill hole in any material up to 1.5mm/0.06” thick."
I’m debating (and plan to test) what would be best/sturdiest: acrylic, ABS, HDPE, etc. I wondered if I could save some time by asking the resident experts.
I’m not sure whether I’ll add a frosted acrylic sheet for diffusion. That’s another thing I plan to test. But it’d be nice if it was finished and clean so that it could be used either way.
Yeah, regarding layout, they’re pre-wired, with connectors every 50 pixels, so whatever pattern I use, it’ll likely need to spiral or zig-zag in some manner. I’d prefer not to cut and rewire to run each spiral arm from the inside.
Thanks again, I definitely plan to post more pics, video and details along the way.