I also square the blocks. I make all my blocks, then measure them and find the smallest one. If the smallest one is really really smaller than the rest, like 1/4", I discard it (or them) and make replacements. Then I square all the blocks up to the the same size. If I do this, then usually the quilt stays pretty square. I just measure the quilt across the middle to get the border measurements. I try and keep my quilting of even desity thru the whole quilt. That's one of the reasons why you get a quilt out of square after quilting. If one area is quilted more heavily then this area will shrink more than the rest, pulling it out of square.