Update - it's likely this one is experiencing predominantly Phosphorous deficiencies due to excess Calcium and Magnesium. I've determined that I've been giving all 4 plants in this run too much Cal/Mag and it's expressing itself in different ways with each plant. Too much Cal/Mag locks out P and K, among other micro nutrients, but the P deficiency is becoming the most obvious symptom in the Dougs Varin.
So this week I've been flushing trying to bring the PPM down to a normal level, which I basically achieved today. Will bring back the 4-8-4 and Molasses next watering at normal levels and hope to finish her up strong.