Love it! I know this is a scrap management technique, but to me, some piecing on the backing is a beautiful way to use what you have to bring it all together.
I've researched so much to figure out what I need to do, I think this really helps me understand, thank you! So I need to enlarge my backing fabric by an additional 8" in width and length. So I know I will need multiple cuts. I am thinking I need to cut vertically at about 1/4 of width of fabric., offset. Then I need to cut that small piece horizontally to add 8" to increase my length first, so I have an 8" square block that I may add another block to it so it will be 16" across. Same concept o the other piece of the backing to add to it's length on that side. Sew both of those additions to the panel sections. And so my 2 vertical pieces are now 8" longer. Then I will add a French braid strip 10" wide between the 2 panels along the length of backing and join them all together. Does this sound about right?