Using a 1/4" seam creates less bulk. I've tried the 1/2 to see the difference on a sample piece and that is the difference I see and it's more noticeable. But see what others responses are. Also if the cutting is off a lot that will make a difference in the look of the quilt. Squaring the blocks as you go will help keep the quilts from being out of kilter or wonky as some say. I am not a perfectionist but I like to get as close as or neat as possible.