I think your quilt and your quilting are both beautiful. I know you have put a lot of work into this and it really looks nice. However, I'm like you , thinking a zig-zag would keep it from fraying. I think when you do the blanket stitch it may be better on a wallhanging that you could wash by hand and even then, it's just too much work for it to fray. I do think your work is exquisite.