When I piece my backing I tear rather than cut the fabric. I allow a wider seam allowance because tearing does compromise the threads along the tear. Since it tears on the grain I get a much truer hanging back plus you're only measuring your piece once. I used to dread having to measure all along the length of the fabric when I cut the pieces. I only press the seam area. By glue basting the batting and putting the backing on top of that when I smooth it on it takes care of wrinkles and I never have puckers and such in my quilts.