Fems via light method has it pros and cons. Mother/father plant will need to be separated from your grow at night or even better a seperate grow area. The grow light runs normal times eg 18/6 12/12, the night light runs 24hrs. Your night light needs to be very low wattage, example I use a growlush fan controller as my night light lol. It sits outside my tent and let's light through one of the mesh vents. This works through veg and flower as long as the plant is mature. The brighter the light the more male nuts will pop, but if your light is to bright your plants will not flower nor produce nuts. Kinda ironic it's useless as a fan controller but really good for breeding.