wesing

I agree with JustaBitCrazy. Your quilting in the white areas will become the star, so I would reinforce the structure of the diamonds with something fairly simple and rigid, like straight lines echoing your piecing. They will make perfect frames for your "flowers."

Also, I would suggest a thread color with a bit of contrast in the white (dark ivory/light beige?), but a something that blends in the dark areas.