I love your quilts, and your inspector (what I can see of him). I think I would second helou's idea of a narrow white border, then the dark border of your first quilt, but then I would bind it with the darkest of the purple fabrics used in the quilt. And I would do the narrow white border 1/3 the width of the darker second border.
But that's just me! Whatever you do will look great with this quilt.
Alison