My goal is to work around the limitation of linked overrides that don't yet work for Materials.
I am able to use an object custom property to set the color in shaders. But I will have complex objects with many different materials assigned to various vertices. An example would be to control eye color, hair color and skin tone color in a character. So I would like to segregate these controls into Custom Properties on the Material level.
How do I obtain access to a Material Custom Property that is a color? Is there a simpler way than this driver approach where I have to edit R,G and B drivers?