I would simply suggest changing out one or two of the 6500K's, and replace with 1-2 10,000K bulbs, or you could do one 10,000K and a 5K with two 6500K's.
You see how some of this is based on personal preference, right?
Personally, 5K is too low to get much red pigmentation to form...it may make the existing red coloration stand out a bit more, but if you don't have much red coloration to begin with, then it won't matter. Hitting green pigmentation with yellow light will just deepen the greens. I recommend that you try the 10,000K bulbs. You may want to cycle those on, but I have my lights on for 12 hours, with an hour of ramp up and an hour of ramp down.