I'm not Mr. Expert and I can't quote you chapter and verse but I think a lot of the rituals people go through at harvest are a waste of time, at best, and counterproductive at worst. For ex., I think dark periods are a waste of time, and flushing is counterproductive (denying nutes to your girls in their last week is nuts imo). Like I said just my opinion, but I feel obliged to warn newbs about this stuff.
As for your girls, I say let them go.
I have 2 8 week strains and I find another week may send me past the "perfect mix of cloudy, clear, and amber" or whatever, but it also gives me denser buds. Not that I have the patience to do that, but there you go.
Those easily have 2 weeks to go. You will double your weight and bud size if you can have a bit of patience. All those pretty white hairs are from new calyxes waiting to give you more weight and smole. Be patient, you will be happy you did.
7 - 10 more days and perfect, only plain water! They are seriously starting to look amazing, that is a really well grown healthy plant. The buzz is going to be fantastic, this is the important part don't rush it! It's all in the finish man.
If what you're growing is bluedream, i suggest you wait a bit long before the harvest , i have grown quite some blue dream before, take my words for what it worths, O and about leaving plants in the dark, you really dont need to lol