Take a swatch of both to a large fabric store. It can be vacation or a shopping opportunity. As long as the blues are in the same color, you can add 2 or 3. Some won't work such as using a teal or turquoise with plain blue and white. It must be in the same color family. Two colors will work, but y9ou really will like working with more. It gives so much more depth. You might try trading some with your friends or quilting buddies. A lot of quilting fun is, shopping for fabric and enjoying all the colors. The longer you do it, the more fun it gets.