Before I trim my extra batting/backing, I sew a narrow serpentine stitch along the edge of the quilt. Then I trim it. It helps hold down the raw edge and makes it easier to add the binding. You could mark the cutting line, center the serpentine stitch over the line, add the binding and trim. Just be sure that the stitch is within the seam allowance. I know it sounds like a lot of work, but it's a bit easier to handle the fabric where the quilting is more spaced apart.