Thought I'd start a unique project, taking a while, but will be sweet when it all comes together:
The coating is Titanium Aluminium Nitride (TiAlN)...
Here are the specs:
Thickness: 1-3 microns
Micro hardness: 2700 Vickers or approx 87 Rockwell
Thermal Stability: Up to 800° C
Friction Co-efficient: 0.4 TiAlN/Steel
So, it's pretty tough stuff!
I thought about white, yellow, Panerai blue, and a cream/bone color, but I've started with a light grey. So far, readability is a bit low, but it may work.
Starting with model paint, a just lather up the whole bezel, when it dries, rubbing it with scotchbrite removes the paint on the bezel, leaving 'some' of the paint in the numbers, but not to my liking.
My next try will be with a Laquer-stick as suggested by heitwl... thanks :cheers: