What's the point? Running the lights more - up to 24 hrs - allows the plants to grow more and faster, than they will under 12/12 - and prevent them from blooming before you want them to. If you run 12/12 light and 2700K, you'll probably have some little scrawny plants, that may may not bloom - or if they do, it'll take forever, and you'll have a tiny amount to show for your effort.