Your quilt is just beautiful, and I bet it will look good however you quilt it! I have no advice on the actual quilting design, just had to tell you how much I like your quilt.
I did, however, just recently quilt my first king-sized quilt and I found several good videos online about how to handle the actual size. You might want to google and see if you find them. The best advice I saw/got was to just concentrate on a small space at once and to be sure to support the quilt well so it doesn't shift. I found that putting my ironing board perpendicular to the left of the sewing machine and at the height of my sewing table really helped.
I was really pleased and surprised at my results. Hope you are the same.
Again, great quilt!
Dina