One of my quilting friends suggested that all the quilt top needed to get those wavy edges straight was to remove the borders, throw the thing in the wash, and the stretched edges would no longer be out of shape. I washed and dried the top, and the raw edges were still wavy. Part of the problem, I discovered, was that all the plaids are of polyester, not cotton, and therefore not likely to do any shrinking.
Somewhere in the back of my mind a thought surfaced: Stay stitching. I used to make a lot of my clothing, and stay stitching is used around edges that might stretch while being machine stitched. Stay stitching did the trick on this quilt. Maybe real quilters do this on diagonal edges all the time, I don't know. I'm just learning as I go.
One thing to remember, which I didn't, is that the fleece has a right side and a wrong side, the colors on the right side being slightly crisper. However, if you look at these puppies, you probably can't tell which ones I accidentally fused wrong-side-up. I left them that way. There's only so much I'm willing to do when it comes to fixing mistakes.