I think you are very near harvest. Flushing is "bro" science. Just time-consuming and a waste of water. The soil nutrient levels should never be at a point that they need "flushing" It depends. I may do a staggered harvest my next round bc I won't be doing another run until spring. so, in that case, i have extra time whereas normally I would want to clear the tent for more space. if you have the time you could harvest the top and let the lowers flower a little longer. but most of the time its better just to make some hash or edibles with it and use your time to start a new run