You don't say how large they are going to be but if they are large enough i would machine stitch it to the quilt before closing it up. Difficult to explain but I will try:
Whatever size your yo-yo is going to finish up, as an example, 2" make up your 5" fabric circle and stitch around the running stitches, easy to do with a Quick Clover yo-yo maker, then BEFORE pulling the thread closed draw a circle, 2" in diameter in the centre and machine sew around that circle thro' the yo-yo and the quilt, you then pull the thread closed, that yo-yo will never come off and they come out so beautifully uniform.