I love your solution. Thanks for updating the thread and us with your progress.

For me, I love the piecing and planning parts, my problem is definitely the quilting...

I would make a solid black border then Piano keys (I love this look) and then another black border. I would finish the binding with the mixed colors from your quilt. This is going to be a fun finish no matter what you choose. Your quilt is so pretty and the colors are splendid!

I really like the checkered border you decided on. Such a pretty and bright quilt. Great job done.