I used spray basting on my first quilt but the back looked a little wrinkly to me and I wasn't sure if it was supposed to look like that so I peeled it apart. It had only been a couple days since I put it together so I don't know if it makes any difference or not. Mine was still a little sticky so when I re-did the sandwich it still stuck together. I also used pins cuz that's just me. If it's worth doing, it's worth overdoing!