I'm glad you're having this conversation about the scant 1/4". I'm a newbie and self taught. This drove me crazy and still does. Some patterns in quilt magazines call for a 1/4" but they really mean a scant. I've found myself having to sew a 3/16" seam with some of the more complicated patterns in order for the blocks to turn out the size they're supposed to. What about when several seams cross each other? The room taken up by pressing is more than a scant. It's almost to the point that you have to guess at what the seam allowance should be depending on the pattern. I've asked myself why I have chosen a hobby that requires so much precision. Haven't answered that question yet. OK, I feel better now.