Back to the original question about light color - If you do decide to go with light rather than UTHs, just go with a normal light cycle. Use white light during the day for viewing and heat, and use a red or black bulb at night (NOT the same as a black light that you'd find at parties and stuff) for heat.
You could also use a red or black bulb 24/7 if you really wanted to, but if you want to view your corn during the day the red/black bulbs will make it look weird.
For what it's worth right now I have a UTH under the viv and a white undercabinet light in the viv itself. It doesn't do anything for the heat, but it lights nice and evenly and doesn't get hot enough to harm the snake if he were to touch it.