I have spray basted my last 10 quilts I think, from twin to full size, and as long as the backing is taut, I have never had a problem with wrinkles. You do have to be careful about overspray, and the batting will pucker if you are not careful in placing it on the backing. I have had some quilts sit for over a year before I actually machine quilted them and the spray held with all my pushing and shoving and rumpling to get it under the neck of my home sewing machine. In the winter, it can get stinky, so I try to baste all my quilts in the garage when the weather is comfortable, and then quilt them over the winter. I would never pin or thread baste again.