I think this is a great discussion to have. Some people have stated that a 1:1 ratio on whites to blues cause a washout appearance but with your ability to regulate voltage should allow you to find the coloration you want.
Have you tried using optics with your XR-E Royal Blue LEDs?
On this thread,
http://www.reefcentral.com/forums/sh...1852268&page=6 lucasabao has recently placed LEDs over his tank and has had decent success with them.