I haven't actually grown any plants to harvest yet, but I've started some grows using different methods in order to refine my setup and get everything right, and it seems that it may work better to do 24/0 for a few days so there isn't too much stretching, then switch to 12/12. I've also read that 12/12 from the start works well for indoor sativa, so you might want to get a packet of Nirvana mixed sativa.