I never trim leaves, they are the solar panels that provide energy for the plant, why cut them off. I waited till like two weeks into flower when the pistils started to pop up and looked at any bud sites that weren't reaching up or bulking up and cut them off one at a time. It wasn't very many sites like three or four, now that my grow has filled in leaves will just fall off at the bottom I wont trim any leaves off if the plant isn't using the leaf it will drop it its self or you will be able to gently tug it off. Let your plant tell you what leaves it wants to keep and which aren't getting any light it knows what to do.
I can actually tug a bunch off of the bottom each day I barley pull and they fall right off.