do not trim leaves at all......unless they are diseased or dead...otherwise the plant will shed as she sees it,usually starting from the bottom up. those big shade leaves are the plants main source of growing energy through photosynthysis..everytime you cut a fan leaf off you slow and stunt the growth of your plant...its healthier for it to remove those lower spindly branches that are being shaded so that the growth is focused at the top canopy...