Is it ok to trim large fan leaves while in flower?

No, don't do it! Your plant needs every healthy green leaf she has to make the energy she needs to grow her biggest and best flowers. Less leaves = less energy = less growth. It really is that simple and basic plant biology. The "bud sites" are relying on those leaves to make the energy they need to grow the buds. Besides, if your plant did not need those leaves, she would not have grown them in the first place! Hope this helps, Organoman. (and MR. Very Anti Defoliation!)