I did a few things differently.

• Made 10 of each pcb in white using the gerbers in the original project.  In white so I could colour them easily.  Reused the supplied green.
• Hand assembled them all, haven't forgotten how to do this - phew!
• Sourced white studs from AliExpress so I could colour them
• Sourced 1.5mm high headers from Digikey (all the AliExpress ones I could find were 1.8mm, too thick)
• Changed the code to drive all the leds
• Reprogrammed using the atmel samice
• 3d printed the spacers as I could not find 1.5mm acrylic

The colouring turned out poorly.  I'm not an artist.  I had planned to mask the leds and cut the sharpies open to pour the ink out but the masking didn't work too well and it seemed wasteful to cut open all those sharpies.

Credit to Debra for the awesome idea.