I think the problem is that, although the textures are at the same resolution - 4000 x 4000, for example - the body covers a lot more area than the head. As a result, the pattern is going to be stretched more, and give you an uneven result.

So that's what's causing the problem. Unofrtunately, as I'm not a texturer, I cant' tell you the solution. :(

jonthecelt