hey man, you can start the flush starting on monday, no problem, just plain water no run off (to reduce the stress) , you will for sure harvest in week 9 maybe a bit earlier. Looks good ! next time to do the timing of the flush look at the trichomes for you right now it's few clear, mostly milky , some amber. next time try for few clear , mostly milky, no amber. You're doing a fantastic job, and when you will taste it you will see how perfect it is ! hope this helps ! 🚀