My daughter does mostly a stitch in the ditch on her quilts. She uses a lot of pins and starts on a middle row and works her way out. It seems that no matter where she starts, she gets some pleats. Maybe if she used the 505 spray to stabilize everything the back would be smoother. I will be curious to see what the experts say. IMO, a few small pleats are not a big thing to worry about, especially if they are on the back. If you just want to stabilize the quilt with the stitches and are going to do some free motion stitching, have you considered buying and using the water soluble thread for your basting? It will all disappear when the quilt is washed.