Great job with the RapidLED kit.
As far as diffusing the red light, you could stick a piece of frosted tape (like work/desk tape, not packing tape which is 100% transparent) to the inside of the splash guard right under the red LED, which will diffuse the heck out of it.
Looks really clean when you have perfectly cut and soldered wires. I just decided to go the messy way, since if I want to swap out LEDs (which I've done twice now), all I do is open the splash guard, unscrew the puck, pull out the leads, plug in new one, screw in, and replace splash guard. No hood removal required (though I should!).
Interesting you went with white for one channel and blue/colors for the other. Blues run at much higher power than even the white LEDs, so what I did was put them on their own channel so that I could dim the color channel but keep the blue LEDs (the PAR generators) higher or consistent, and blend to those. It's worked out well, but to each their own.
But it looks great, and I'm sure you'll have a great outcome with them!