I would take the FARTHEST leaves and growths off the bottom but leave the bottom middle and middle fan leaves COMPLETELY in tact, you will need these for nutrients when you flush. then I would ALSO take the VERY top LARGE fan leaves that block light to the middle growth shoots. So our aim here is to clear out the EXTREME bottom so we have airflow to prevent mildew and mold, the growth shoots as well because they will never mature(be sure not to trim a branch which is supporting an upper growth shoot). Leaving the bottom middle and middle Large fans for photosynthesis and nutrients during the flush. Lastly taking the top SHADER FAN LEAVES to provide light to the middle growth shoots and fan leaves.