After a few weeks the PWBs have arrived!!!
I started with the display boards as I new they were going to be a little finicky to get everything lined up. Managed to get the connectors all 16 boards lined up. I may or may not have had to reverse things a few times.
All 16 boards connected.
Now to install the discrete components, MAX7219s and displays. After installing parts but before cleaning.
Now time to test!!!!