The center and quilting is beautiful. I would lay the blue feathers out as you have shown in the (browns) photo. I would start about 1/3 from the right corner on the bottom and have the feathers go up the side until I ran out of feathers. (Starting on bottom, up right side and around corner on top border—you get the idea). (Leaving a lot of blank (feathers) on the left borders. I would “attach” the (individual) feathers to the spine with my quilting. When I ran out of (blue) feathers I would continue to quilt the spine and feathers around the rest of the border until I met up with the bottom where I started. I would blend my thread. I hope this is not too much information on what “I” would do. :-)