I starched the back once, but then saw that the back was just as wrinkled as the times that i did not starch...I starch the front as i go - paying attention so that i'm not stretching - that has been a large learning curve!!
My key is to baste my quilt sandwich really well to prevent puckers and movement when i quilt. I remove the basting as i go.l I will also add that i hand-quilt, so don't know how that works if someone is machine quilting...