All I can say is "WOW!!". Absolutely stunning. If the quilt size is what you want, I'd just do the darker border & binding (I like the navy idea). If you need it just a little bit bigger, I'd do a 3" navy border, followed by a 2" strip that alternates various colors in the quilt (those would be 2" long each) and finish up with another 3" navy border with binding in navy. It would just nicely frame all the gorgeous blocks. How are you planning to quilt it?