If i caught it right my 2 disnt start flowers till 35 days. A bit long when some start at 17 days XD so 4-5 weeks is a safe bet to count the start. 7 weeks of flower would put you at 84 days ish. Now since they could've started at 4 weeks, 77 days is where i would really look at trichs, but if you're already at 70 days id check them 1 time a day. How do you want it? Racey/head type of body/couchlock? If first type than they will harvest early when mostly cloudy white and few amber. If second let up to 30-50% amber. Mix high maybe 80 milky and 20% amber. I like as much milky and little amber as i can get.
