I usually like to border my quilts with the darkest color on the outside....it sort of frames the quilt blocks....but obviously, there are no quilt police here so do what looks best with the blocks. The one thing I would recommend about the borders is to make sure that you cut them length of fabric instead of width of fabric because they're less stretchy. I think on a normal quilt it doesn't really matter but because your pieces are so small, I think you need the grain of the fabric to help you hold them steady.