When to top at the lattest ?

I will start cloning in 2 weeks and was wondering when was the best time to â??topâ?� my pants before putting them in the flowering light cycle ?

Is it a bad idea to top a the beginning of 12/12 and if so, how much time should I wait between the final toping and the introduction to 12/12 ?

Instead of topping, try gently bending the plant, one way one day, the other the next(bend right over ei. 120 degrees) This will encourage more lats to grow without shocking the plant. you will end up with a bigger bushier plant.;)