I test-fit the core lighting system on the ceiling and tried out the white LEDs (up and down at the same time). Interestingly, the upwards white LEDs create a very rectilinear shadow of the wires on the ceiling. The effect is not bad, but also not intended. I'm going to roll with it, though: the room illumination it provides is excellent.

The RGB LEDs work great too:

Of course, this is only showing off the fact that all the LEDs light properly and checking out the light levels. Every one of the LEDs can be controlled, there's a ton more possibility than just a single color at a time. The downward RGB LEDs will be diffused and the upward ones will just have a clear dust cover on them, so the final effect will be very interesting.