I was playing around trying to figure out why I wasn’t getting the expected color brightness. I finally thought to load my sketch onto other tiles. It looked much more reasonable!
The LEDs are much brighter while the blank is connected to the pogo pins compared to when the tile is powered off the battery. I tried setting the board switch to “Power Target” and “No Power”. The former is super bright. The latter is a bit closer to what I expect, but flickers slightly.
This means I effectively need to test by battery every time in order to see how it will “really” look.