Faced the same problem with some pre-printed Asian themed panels a while ago. Ended up trimming the panel sashings to 1/4" and adding new sashings -- think I started with about a 2" strip, and then cut those all to a uniform size. Cannot be seen in the finished product, and since they were square in the top, the quilt came out square too. Good luck -- the fabric is very pretty and should make a fine quilt.