I did basically the same thing with a king sized duvet cover. You start with the center square on top of the batting and backing, sew that down, then add the next strip and sew that down to the sandwich and so on. When I made mine, I top stitched on top of the seam to keep the seam secure. After top stitching it, the quilt is very secure and looks pretty. You could easily do a narrow top stitch and it would secure the quilt and make it look quilted. I found this video (
http://youtu.be/rl_OPPpXNLM) on youtube if you need additional instructions.