Some plants like to be topped, others don't. I have a Northern Lights that bushes out on it's own, with at least 8 tops with large forearm size colas, topping that would do no good. My afgooey however loves it. I topped it only once, changing 1 top into 3, let those 3 tops grow 1-2 feet tall and then bent them over in a peace-sign shape. Now i have 25+ tops that will grow another month before flowering out. I will get 1 LB easy, but that northern light yields 10 oz all on it's own. So should you top your plants? Experiment, find grow one out and see how it likes growing naturally, notice the plant shape. Maybe grow 2 or more of the same strain, topping half of them and growing the second half natural, science is fun.