I used all black too..
Here's my problem, however:
I temporarily printed my CPO on a crappy inkjet plotter.. It's very dithered, and while from a distance it still looks great under the plexi, up close it starts to look crappy. Also, I ran out of funds before getting all of the correctly colored buttons, and eventually have to remove the plexi and CPO to put in the new CPO when I get it.
What I'm worried about is... I'm going to have TONS OF MICROSWITCHES, not connected to buttons, ALL WIRED THE SAME COLOR. I guess I could turn on the computer and manually click them to find out where they go, but it's going to be a nightmare.. I REALLY wish I had done it differently now.
--NipsMG