Well come to the board from Pennsylvania.
I have made 2 dresden plate quilts. Both of them were with rounded edges. The first one I made I turned under a 1/4 inch on the edges and appliqued them to the blocks. I didn't cut away the fabric that was behind the plate. The second dreden I did a little differently. It too had rounded edges. I placed a piece of fuseable webbing sticky side facing the right side of the plate. I stitched around the plate 1/4 inch. I then cut a slice from the middle and turned them right side out. The next step was to iron the plates to the background. I did a heavy blanket stitch using #12 Sulky cotton thread to give it a hand stitched look. Hope this helps.
Peace and Blessings