BreaknNinjaFruit

I'm going to go on a different route regarding your symptoms. I see purple to blackish dead splotches on lower leaves, severely affected leaves with metallic purple color contorting and withering, those are textbook symptoms of phosphorous deficiency. Since you don't mention it I assume you are not measuring nor adjusting pH. I believe you might have deficiency due (a) pH been in the wrong range, or (b) after 6 weeks of veg growth that 1 gallon of soil is somewhat exhausted of nutrients, so either pot up to bigger pot or start feeding.

Do it after day 21 of flower or you might stunt the stretch phase. The idea is to expose leaves that are connected to lower buds that are otherwise shaded by upper leaves. Some strains don't need to be defoliated, and some others have elaves right on top of each other, which promotes high humidity, which is something to be avoided. If you've never done it, don't over do it, you can always pluck some leaves at a later day. If you look down on the plant from the very top, a defoliated plant should have enough foliage that you still see green, so the light won't just reach the soil