The pieces on Butteryfly are very thin. They are about a quarter of an inch at their widest. I knew that I needed to adjust he size of my double blanket-stitch and make it smaller so the stitches didn't go too far into the fabric. I decided to test out stitches at 1.4 millimeters wide and 1.4 millimeters long. I was very happy with the results. The stitches stitched out well (I tested this first! A MUST!) and I was a happy camper. The yellow thread is Polyneon by Madeira threads and the pink is a Sulky Rayon 40 weight thread. I chose these threads because they were the right color. I knew that if I stitched the wing pieces in pink or purple thread it wouldn't work because some pieces were predominantly pink and yellow and others were predominantly purple and yellow. Therefore I picked yellow thread.
Of course, I forgot to take a picture of the butterfly before I layered the quilt, so here it is with the pins already in. Oops.