spectrum question

I have a mix of warm and cool spectrum lights for flower production should I continue using the cool mixed in or should I phase them out in favor of the warm spectrum bulbs? The plants are in their 3rd week of flower and seem to be responding well to the mix of both.However the plants are as tall as I would like and my concern is thus.

For vegging I do 25/75 3000k/6500k. For Flowering I do 50/50. When they start getting too tall I take string and tie them down. Bending them over. Do a search for super cropping. Hope this helps