Can you clarify what exactly you mean by "choked off"? Do you mean the scrog screen is applying too much pressure to the main branch or are you talking about not enough air flow under the canopy? The screen was added a week ago and the main branch is bent pretty drastically in order to fit under it. My cabinet is only 2.5' x 6' and I have 1200 watts going over three plants. The VK took off a lot quicker than the Tahoes and it is a massive bush. I can hardly see through below the canopy. Tons of growth under there. I added two small Vornado fans blowing straight up to try and get some air blowing through there. Another thing I should mention is I did change out my reservoir a couple days before I started to notice the problem. Using GH floranova grow up until this last change and switched to half floranova grow and bloom this time. I took the ppm down 100 from what I had been running in veg. They have been drinking this new batch up like crazy, about 4 gal between the three plants a day and lowering the ppm by 120 or so every day when I top off the reservoir. PH rises every day to 6.2/6.3 and I lower it to 5.8/5.9 every day when I top off. It has been like this from the start.
To answer your question, 5 days ago I noticed that some of the lower leaves started to have a "silky" feel to them, like they had lost all rigidity. I didn't notice the stems feeling soft until yesterday, which is when the leaves started to completely fall over, looking like they do in the pics. The branches they are attached to still seem fine, or at least they still feel like the other branches on the plant not affected. I have been keeping a close eye out for any signs of mold/mildew everyday, and I haven't noticed anything on the leaves. But again I am new to this so the only thing I have to go by is message board posts and pictures, no real world experience dealing with it.
Once lights come on today I will do some trimming. You said to trim away the affected leaves, do I cut off the soft stems they are attached to as well? You also mention trimming away any shoots that didn't make it above the screen. The screen has only been in there a week and their is a ton of them still under there. Take them all off? That is going to be a ton of plant I will be taking away. Thank you for your help