Glad I didn't attempt to miter these borders-I have a 4" strip of the dark blue border fabric left! Whew! I added cornerstones of the outer border to accomplish the effect I wanted. Thank you for the suggestion, Maggiemay! I think next time I will just do the borders separately....but this project needs to be done asap, so I took the path of least resistance! It's raining and the lighting is terrible-the blues are rich and the medium blue is so pretty. The lightest fabric is also blue-looks white on my screen! Close up is more accurate....
Thanks everyone for your input-this is the best group of quilters ever!