The two clones in my thread Wicked Widow were taken after the branches started alternating. No need to go 3 weeks into flower. As soon as they alternate the plant is sexually mature. I like to take them slowly from 18/6 to 12/12 over a period of 2 weeks and catch them when mature and alternating but not flowered yet.
If you scroll down that thread you will notice there is at least one picture of the bottom branches and they are alternating and not double.