To my eye the blue does not play off of the print the way the orange and purple do. BTW on my monitor the top looks orange and middle looks purple and the bottom looks very pale blue.
I would use both orange and purple! You could strip piece chinese coins or cut 3" by 6" retangles and lay them out brick style to finish at 2 1/2" x 5 1/2". Two rows laid out the long way would equal your 5" needed.