I'm a firm believer in pressing/flattening the heck out of a seam, so seldom need a 'scant' 1/4" seam. If I'm making HSTs or QSTs, I try to start with larger pieces of fabric, then stitch and trim to size. If I'm given a square that's not cut quite right (as in an exchange), I may use a 'scant' 1/4" seam on it, to compensate.