I was reading the other day about the scant 1/4 which is actually a 3/16th of a seam so you need to check out your ruler and look at how little that amount is and if you pull back your seam line just that smidgen more every single time.. you will get your block the right size (assumingyou cut things the right size). I did it and whola, my block was now the right size. The other thing you can do is simply go as you are and if your blocks are 12" unfinished then thats the size they are. And not let it get you.