Your piecing is superb... I love the monochromatic.. I can't imagine the green border... I think it would be too distracting. With all that beauty you don't want that to happen.. The shortfall cornerstones, and I have had that happen was serendipitous. They look like they should be there - especially since you used them elsewhere. I would call it done and bind in the bright red so that it really stands out!!! You did great and should be sooo proud of your self and not stress over the small stuff...