I'm just reading this and am wondering if you put the ruffle to the back of the quilt, with the wrong side to the quilt back, then put your binding on the back on the ruffle, line up your edges and stitch. You'd then fold the binding to the top of the quilt to finish.
Another thought, which would reduce bulk at the edge of the quilt...attach the ruffle to the binding at or near the fold line of the binding, then attach the binding to the quilt as normal, fold the remainder of the binding to the back of the quilt as usual and attach. Hmmmm....I'm doing this with paper at my computer, may need to go to my sewing room and try with fabrics.
Beautiful quilt - good luck!