Well, the light bleaching is a result of so much raw photosynthetic power hitting the plant. As chlorophyll does its thing, it literally dissolves and reforms. Light bleaching occurs when the rate of photosynthesis is so great that chlorophyll can't regenerate fast enough to keep up with the incoming power.

Working with different wattages of LEDs is, IMHO, asking for a higher risk of the equipment failing. Different diodes of different wattages have different operating conditions, and thus it is likely that having .5w diodes mixed with 1w diodes would cause the .5w diodes to fail pretty rapidly given they're more sensitive to heat.

As for wasted light, sadly this is what happens with ANY light solution. Due to the recessed nature of the LED board inside the panel housing, the outer edge LEDs don't get a chance to blend (and this is why you see that off-colored outside ring of light from any panel) so the center dominant color becomes the outer ring primary color. Once we can get panels that aren't designed with recessed boards made, then we won't have to worry about such wasted light.

Also, bear in mind that a 120 degree viewing angle was meant for shorter and more compact plants, as such a wide spread cannot penetrate to the degree 90 or 75 degrees would due to the wider spreading of photon emissions.