I love your scrappy Dresden plates, it's going to be a beautiful quilt. When I made my Dresden Plate quilt I used the pattern from Eleanor Burns and Quilt in a Day. Eleanor makes a circle of fabric, with a circle of fusible interfacing, then she sews around the circle with small stitches, trims the circle, cuts an opening in the middle of the fusible interfacing, turns it right side out, using a knitting needle or other type of tool, then places it in the middle of the Dresden plate and irons it on. It will stay in place until you do the final stitching around the center. It makes the Dresden Plate a little bit easier. You can also go to Quilt in a Day.com to watch one of her videos which will probably explain it better than I just did, but her method works.