PS I have had that sort of issue. Found out I had to measure through the center lengthwise as well as along the edges, maybe even a couple of other measurements, then figure the average of all these measurements. Finally, cut the side borders to that length and ease the quilt to the border. Helps to pin ends and centers, also the quarters, etc. Same for the horizontal borders. Did this make sense? Hope so! They usually come out pretty well for me now. Happy Quilting.