If you are trying to go for a plant light, the 6700K is better than either of those IMO. Both are at the top end of the spectrum for plants so between them I would favor the 10000K. If you want to light a reef tank then you might use the 12000K instead. Natural sunlight, the stuff our plants are fully adapted to use after many millions of years of evolution, runs between 5500K and 6500K depending on what source you believe. The higher temperature, shorter wavelength of your selected bulbs is far from ideal for a plant adapted to real sunlight.