Beautiful!
Your batting selection will help determine how much you can leave unquilted.
I think I would SITD around the outer edge of the beauties, then do straight "rays" coming from the center of the circle block: start in the corner of the blue portion of each quarter circle, and go to the outer edge of the circle Maybe 3 or 5 rays in each quarter circle.
Then I would do a smallish meander in the other portion of the blue background.