Windsor patient

I am currently growing in a tent with a 40,000 lumen T5 system. I have currently one intake fan and I'm assuming with no (wide) open vents with positive pressure. I have a 12 plant aeroponic system that is currently being used to its full potential. I'm not looking to switch to HPS. I flowered fine with this before but what I want to know most is when should I flower. I'm currently at 4 or 5 weeks into growing. I'm on an 18/6 lighting schedule. When should I switch to 12/12. The last time was complicated. I started with dirt and cloned but this time everything was from seed. I just want to kill off male plants once I sex the plants and let the females flower until maturity. I would also like to know if I could clone during the flowering stage?

Here is a link to the video: YouTube - Medical Grow 4th Week