OH MY! That is a beautiful quilt and your hand-quilting is gorgeous! I am mainly a longarm quilter, but, I think simple quilting in the border would be best, as it is a busy border made with several fabrics. How about piano keys, with each key being the same width, and lining up with the small squares in the blocks? I think it would be easy to mark and quilt, but very effective.
Karen S. in Columbia, la,