Well, again, it's a very narrow view to ascribe only one factor as being the only factor in a coloration. Intensity is a key factor. Plants produce pigments to protect themselves from the radiation. What folks don't seem to realize is that the colors that we like to see in plants is actually a defense mechanism to minimize radiation poisoning, in the same way that pigment cells in our skin protect us, to some extent, from sunburn. There are many reasons for pigments and the plant will allocate pigment types in response to the environmental stresses they are facing at the time. The resulting colors that we see are a combination of the various pigment types that are produced based on each type of stress.
The plant also has to be able to assemble the pigments, which are very energy expensive, therefore, CO2 and nutrition plays a key role in whether or not the raw ingredients are available to fabricate the pigment structure.
Chlorophyll is a Nitrogen hungry pigment and it is green. In a Nitrogen poor environment and under high lighting, the Chlorophyll levels will be minimized and that will reveal the other pigments that are produced as "sun screen", but, if that is taken too far then the plant will become weak and there will be health issues.
Genetic is also a factor. It's always best to get plants that genetically have large amounts of the pigment colors that you like. That makes it a lot easier without having to stress the plant.
So in fact, just because Tom has a certain combination of bulbs it doesn't automatically mean that the plants in your tank will look as nice as his. It is the totality of all the things he does in his tank that produces the results you see, not just the bulbs. Having said that, if you add a lot of red diode or red bulbs, of course everything in the tank will look more red. That goes without saying. That includes the fish.
That's why I'm saying that you don't really have to worry about what Kelvin value will grow the plants, but if you want to add the illusion of color then use a combination of bulbs to produce the visual illusion. That is what Tom is doing with those bulbs. He did not calculate what Kelvin colors were optimal for growth. He simply likes the colors that the combination of bulbs reflect on the tank inhabitants.
Here is an example of the fickleness of color. These are two branches of the same Pogostemon stelletta specimen. Under the same set of bulbs (in this case, the supposedly 4000K Osram 840 T5), the two branches stting right next to each other produced radically different colors. I have no idea why. We simply don't have enough control or knowledge right now.
Cheers,