i have topped a few clones, and left a few alone. in the same amount of time, both gave me apox the same weight, but the topped 1's was smaller buds. if it was indoor, i would say "NO TOPPING" you want straighter, less branched plants. but if outdoor, and you need to control hight, go ahead, but of topping, wait for every 4th or 5th set of leaves, then you wont shock it too much, it will still have some strength to keep growing, and you get more branching by less topping. my mom swears by topping every 3rd set, but her plants grow so slow, i never saw the use of it. she does it to keep them under 4 Ft when completed. and her plants are about 8 Ft around. they are like hedges. she does 4 along the back of her house. but she only gets 5 Oz per plant or so. when i dont top, i get 10 to 25 Oz per plant, depending on strain. if i lightly top, for hight, i get 8 to 16 Oz. per plant. and never remove leaf matter, until it is dieing off naturally. think of it as a solar cell, it is how the collect light for growth.
its free.