I use the "scant" but as long as you sew all your seams the same all your blocks should measure about the same. Just don't square up your blocks until they're all done then measure each one. Square them all up to the same size as your smallest block. When sewing angles (such as half square triangles) you can really get into some problems. The first time I did it, my 12 1/2" block measured 11 3/4". I just trimmed it down a little more and put a narrow border around it to bring it up to the size it should be. It looked great in my Civil War Era quilt since there were several blocks with those added borders. Sometimes you'll have to do some adjusting with the width of your borders or even add or take away a border to get the size quilt you want. The thing to remember is that each quilt you make it your personal creation and doesn't have to be the same as anyone else's. If it's a little smaller or a little larger it doesn't really matter.