I'm getting an odd problem at this stage where when I go to paint on the C_base texture with my brush it does it like a stencil the shape of my UV. Utterly weird. I can't think what I might have done to make that happen.
If I am understanding your problem correctly then this has to do with your brush mapping. While in the texture painting window, go down to the "Texture" tab and change the brush mapping from stencil to something else like tiled.
