LOVE your quilt top--It's absolutely GORGEOUS!
Hope this gives you some ideas...Here's what I did to FMQ a large runner. (I plan on adapting this design for my quilt when it's ready.) I wouldn't quilt the middle squares as heavily as I did on this one for a bed quilt though; I posted these pics just so you could get some idea of where you might like to lay out designs.
Your quilt top is so beautiful already, that I'd keep the quilting simpler, probably feathers down each side of the braid and just enough in your focus squares to accent the fabric designs nicely. I think for your quilt top, some contrasting quilting on those purple sashing pieces would look wonderful--what about a "curly ribbon" or swirls design? Both are pretty easy to FMQ, and would look great. I think I'd use yellow thread to match the little stirps beside it.
This is the back. It gives you a better view of the FMQ