One thing we haven’t really discussed in detail but we have to a small point what’s the fact that I believe you were watering a little too often. I suggested that you give up that watering schedule and start lifting your plants and feeding them when they feel like a loaf of bread rather than a gallon of milk.
To further elaborate, over-watering practices will lead to wilting curling leaves that also get spots. I believe back when we were discussing this matter that you were demonstrating watering practices that proved slight over watering.
So hopefully you’ve gotten on top of this as I believe it could be a contributing factor.
We’ve given your plants sufficient potassium and phosphorus that would fix any deficient plant. With that said it’s important to take note of your new growth and confirm that none of the new growth are showing the same signs.
Thank you for spreading the girls out into individual pictures this helps me identify each plant much better by its visual appearance.
My assessment of each individual plant
Plant #2 (picture number one)
This plant doesn’t look as if it’s nitrogen toxic from my visibility of the image. The brown spots are noticeable yet could be older leaves from the original issue. I do see the blackness that you’re calling genetic to the strain and I’ll agree with you. Yet I would like to point out just for the record that cold temperature drops can cause black/purpling of the leaves. The trichomes look nice and for this particular plant on the next feed I would return to…
3ml Silica
3ml Calmag
Micro
Grow
Bloom
Voodoo Juice
(No additional additives)
Plant #3 (picture number two)
This plant the wilting and brown spots definitely are more aggressive looking but also hard to tell if there’s anything on new growth from the images that I can say. I definitely see the black and I don’t see dark green that would indicate nitrogen toxicity. On the next feed I would return to…
3ml Silica
3ml Calmag
Micro
Grow
Bloom
Voodoo Juice
(No additional additives)
Plant #1 Picture #3
This plant shows more new growth yellowing possibly calcium/magnesium with less brown spots than any other plant. A few dry Taco looking leaves. On the next feed I would return to…
3ml Silica
3ml Calmag
Micro
Grow
Bloom
Voodoo Juice
(No additional additives)
Plant #4 picture number 4
This looks the healthiest of all plants. Again I see no signs of deficiency or toxicity due to nitrogen. No wilting. Overall wonderful looking health. I would return to…
3ml Silica
3ml Calmag
Micro
Grow
Bloom
Voodoo Juice
B-52
Vegetable fruit yield enhancer
Overall assessment
I believe the first three girls getting a nice cal-mag and base nutrient with voodoo juice will put them exactly where they need to be nutrient-wise.
The last girl returning her to normal feed and I think she’ll do just fine.
I know that the last feed that you’ve done will replenish any nutrient deficiency that you possibly could have had for maybe the exception of iron. I truly believe that the watering was slightly an issue and I hope that you’ve sharpened your pencil when letting them perfectly dry rather than utilizing a schedule.
I also believe that keeping your environment 100% in check is going to be detrimental to the remainder of this grow. Are you having any issues keeping the temps and relative humidity in check?
I forget what kind of light you have but I strongly suggest you reevaluate your lighting and utilize the manufactured height and percentage setting recommendations of your lighting manufacturer for mid to late flowering stage.
Honestly, to the best of my knowledge we’ve done everything we possibly can to rectify the plants. Other than flushing and I personally believe flushing is not a solution and don’t recommend doing it.
Even the cut back of nutrients that we’ve done and the additional nutrients that we’ve added to adjust deficiencies have been more than adequate to give your plants the sufficient nutrients that they needed during this flowering stage.
The worst case scenario. You’re in week 6 getting ready to go into week 7 your plants will finish perfectly due to the advanced stage that they’re in. You have so many salvageable leaves that are non-issued to carry your plant from here to harvest.
Let’s resume the above changes and closely watch the new growth. As you already know the old growth Browning issues ETC are not going to fix itself.
Questions? Nows the time. I just lost my best friend/brother of over 40 years last night from a heart attack and I’m just devastated. I’ll assist you as always to the best of my ability. 
Also you say one of the plants is definitely dark green nevertheless from the images I can’t tell which one that is please tell me picture one two three or four
