I don't know the thread you mentioned, but I often use a narrow stop border before adding wider ones. It acts to contain the center design and gives the eye a place to pause, but not stop completely, before continuing on.
Unless the center is very dark, black acts too much like a dead stop. You want the narrow inner border to act as the thin mat color in a double matted picture, not as the frame. Frames go on the outer edge, not somewhere inside. ;)
If you do not actually use a color contained in the center, the color and value should certainly compliment those colors. Again, think of picture matting. The width should be proportional to the quilt as a whole, but I find that an inch works well for most.
There is an excellent free sample class at Quilt University on how to choose effective borders for your quilt,
http://www.quiltuniversity.com/registrar_free.htm