I can't imagine any quilt design too formal for hand or machine quilting when the right pattern and thread are chosen. Look at some wholecloth quilts -- you can't get any more formal than that and those that are hand quilted are stitched with the running stitch. If you want to use embroidery stitches I would suggest you add them to the quilt top only. I don't believe those stitches would adequately hold the three layers of the quilt together. For some quilting ideas check out Pinterest and look at some of the quilting designs there. There's also a blogsite "Celebrate Hand Quilting" that posts pictures of quilts. When you log on be sure to find "Andrea Stracke" in the lower left column and click. You will find some outstanding quilts there.