You can flush your plants whenever you wish. Though with an autoflower having a defined life cycle I would think depriving her of food at any stage other than the end will most probably slow her down by my eye shes a little light in the middle and looks pretty dry I would say if anything to feed her. though always shoot lower than the guides autos are very prone to take less rather than more. I would keep the EC below 1 personally and you will find the majority of autos will build most mass in the first few weeks of flower they pretty much explode with growth from my experience anyway. Flushing before switching cycles is only really done with photoperiod strains. I know green house seeds have a very flush friendly grow style maybe look into that ? hope this helps bro. Shes looking great anyway defo doing the breeder proud :) 👊