Great blog, thanks for sharing all the details, nice concept and it looks great in action.
One suggestion when it comes to color tint, use a two color tint. One color that effects the lighter colors and one that effects the darker colors. It offers a lot of versatility. (If this effect does not already exist, I am going to look into creating one). Then, you can use a base grayscale image that will be tinted.
Example of the concept (from Spine.)