Grayscale Trial 2.0

I tried it a different way this time. I set the brush to Color mode and then did some very minor touchups with the dodge and burn tools. I'm only posting this so I can get an opinion on whether or not you guys see an improvement. Again, the shading work is shoddy, I'm just looking for critique on color. This is supposed to be a palomino paint with white markings and a white-ish mane and tail. I'm working on a super-secret grayscale project of a certain famous palomino and I want to be sure my colors are correct.

Here are my questions:
1. Good color for a middle-range palomino shade?
2. Mane and tail a good color for white-ish?
3. How "natural" do the paint markings look?
4. Are the white markings white enough?

Thanks guys, I really appreciate any help you can give me on this.

Credits:
Photoshop w/ tablet.
Lineart by ~Falloway
Color n such by Rebecca Wright