I'd try out a few and see what they look like before deciding. Each color will give such a different feel to the finished quilt. I think a narrow in one color, then a little wider white, then a wider in another color. Binding you could test drive that too based on your other choices. Most often I use the same for binding that I did for inner border. I would not use white for binding. Start with your favorites and see where it leads you.
It is a great quilt by the way!