I do/did pre wash both towel and fabrics. I did a free motion pattern, don't remember what, the one that was not as close actually came out the best. Because of both the spray starch on the fabric and the spray adhesive, I prewashed the finished towels.
Can I tell you the comment from my 9 yr old GD. She did not understand the towel and qullt combo, I heard her Mom in the background, the quilt part it to lay on , and the towel is to dry your butt. LOL