By hand, you can't really use a machine w/ PLA as you'll start melting it within seconds.Are you sanding by hand , or power tool? Sanding a mm of pla by hand sounds like a pain!
Going to use a different device for LED control. Sub $10 RGB controller from Aliexpress.
Open it up. Using an ESP8285 controller.
Take out the trusty TS100, flashed w/ custom firmware. This thing was a game changer for soldering IMO.
Did a quick and dirty solder job to attach RX/TX, 3.3V, ground, and GPIO0 so I can flash the firmware on PC. Flashed it to ESPHome, which allows me to use the GPIO to my own specs and will sync to my home automation software, Home Assistant.
Resleeved the power button w/ small diamater wire. And also was able to sleeve the USB-C cable.
I took the whole case apart and spend a rather long while sanding and painting. Also went over the whole case again w/ a jet black lacquer as I didn't like how uneven the bed liner looked. It still isn't perfect but it looks a lot better. And as you can see the PCIe cards do fit properly now. Also painted the white plastic parts of the motherboard to a silver-ish colour. It is peel-able in case I ever need to warranty the board.
Finished wiring up the chassis fans. They all get power from the water-pump header on the board, and then the fan control runs under motherboard to the back near the PSU. Small covers that cover up the cables/connectors.