OK, this is the way I bind my quilts. Firstly, I square up the quilt (all three layers). I have never sewn across the perimeter of the quilt unless on the bias, I would then do it so it would not stretch. I then cut a 2 1/2" binding, press in half, and my sew line will be at 1/3 of the binding. The second third will be pressed up, and the last third comes down the other side, that way my binding is nice and full. I also sew the binding on the bottom first and fold over to the top and stitch it by machine (the opposite if hand sewing). Good luck, I'm sure everyone has their own opinion but I have been quilting for nearly 37 years and have done it that way with great results.