I don't believe in defoliation at all.
The plant "knows" what it is doing.
Besides, if it would not need those leaves, it would not grow them in the first place!
Remember too.........ALL of the plants energy to grow (the buds) is made in/by the leaves.
Less leaves = less energy being made = less potential growth.
It really is that simple!
35-40 years ago when I first started growing, people told me that removing leaves would "let more light onto the flowers and they would grow more", so naturally I tried it many times.
Then an old Hippy saw my plants one day and couldn't cope with what he saw, he was absolutely disgusted with what I had done.
So he told me to grow two plants, one untouched and one defoliated, which I did.
After this I never defoliated again!