I def recommend topping, and lettin em veg out big, at least until the preflowers show sex, and then cull the males, and let em get even bigger before u induce flowering... Itll be well worth the wait, if u have the space for plants that will be 2- or 3X the size they were in veg before u switch to 12/12... If u go now, u will dramatically reduce your yield... Just let em go a while longer before u switch em... And, put em in bigger containers, too... Those r REALLY a lil too small to go onto the next level, anyhow... Thatz my opinion, for what itz worth...