Seems this is a heated debate amongst growers. I personally will never take anything off the top. I do trim on the bottom to allow more air flow on the bottom of the plants, especially if there is nothing but air-y small buds on the stems. You could try bending your plants down to allow more light to penetrate deeper into your canopy, or perhaps spread your plants out a bit? Do you have a light meter? If not, grab one, they are sweet!