Liking quilting I am chuckling also as I just completed my third top on Thursday and asked for help from others in the quilting group as I just discovered that one side was 1 1/4" longer than the other. These are actually from the first blocks I made. I detoured and made another one first. I was assured that the difference was insignificant and that I would just ease it in. So I guess I will be square!
I am aiming for what NJ Quilter says, if you have paid attention to cutting and seam widths then it should be very close to square already. And if it is that close would blocking it get it any better?