Each healthy leaf you remove will decrease your plants ability to make energy for growing/flowering. My advice is to only remove leaves that have gone yellow, for by then, they have served their purpose. The older leaves will naturally/generally go yellow during flowering, despite how healthy your plant is and how well you are feeding it, due to the plant "recycling" elements such as carbs, sugars, amino acids etc. that are basically in "storage" in those big fan leaves. It is far more efficient for the plant to "recycle" the "stored" elements than to manufacture them from new, as to re-manufacture them from new will take energy away from the plant, energy that should be going into flower growth. So, by removing healthy leaves you are doing 2 things to your plant - 1) diminishing its potential to make energy, which can result in smaller plants and flowers, and - 2) depriving it of carefully manufactured vital elements that it has cleverly stored in those big healthy fan leaves. Plants can not "channel" energy into specific sites such as flowers, all energy is equally used throughout the entire plant. Flowers that seem to be shaded will still grow, those leaves people worry about doing the shading, are actually the leaves that are making the energy to grow those very same flowers!
Less healthy leaves = less energy = smaller flowers. It is that simple! Cannabis plants have not evolved to get rid of their healthy, vital leaves during flowering. They have evolved to breed to their highest potential, and this includes keeping all healthy leaves to make energy to grow the best flowers it possibly can.
Hope this helps... Organoman.