After experimenting with my plants I find defoliation to be more detrimental than beneficial in most instances. Heavily defoliated 2 of my girls & left the other 2 alone last grow. The buds on the untouched girls were much bigger even though the light did not penetrate as deep. I found when you defoliate you may increase the number of nodal areas thereby increasing the number of bud sites but those buds will be smaller than if the plant is left to its own devices. The buds need those large fan leaves to make energy which increases bud mass. In other words defoliation increases the amount of popcorn bud you harvest.