Also....this may be debatable, but in my experience, any time you use black or another very dark color in the actually jersey (not the always lettering/logos) it is necessary to also use the "light" shading option, on around 15-25%. Otherwise, the dark section of the uniform (in this case the undershirt/collar) will come out flat.
EDIT: I'm no pro at this, so please understand it's a suggestion and nothing else.
