How late is too late for defoliation?

Defoliating late in flower is never a good thing stresses out the plant a little bit slowing down bud production . You can take a way a few leaves at a time if they are shading other bud sites but be sparing about this if you feel that you have to do it to many sites do a little bit wait a few days like 3-4 to see how your plant reacts then repeat this process until your happy . Usually people will do a heavy defoliation just before the start of flower in order to make the plant focus its energy to the growers needs . From what I can see in your diary you are well on your way to getting some kick ass medicine ! I hope this information helps you understand when to defoliate and when its acceptable to take a way a few leaves . -Happy Growing!