Ahaha sad the mad man.... I see.. this is a strain issue.... you have no way of knowing which plants need what nutrient wise.... I've always wondered how that would go, having more than one strain in a DWC set up, or sharing drip systems. If the two need more food, you have no way of knowing if the one doesn't and is holding up res ppm swings... As long as they are sharing a rez, I'd do just like you are doing and play safe and low... adjust 50 points per watering and look for signs of trouble or accelerated growth. You might just find a middle ground that both strains can live with. But if one is an aggressive feeder and one is not, the aggressive will suffer stunted or delayed growth. I'm interested in hearing other opinions as well, because I just made some DWC systems and was curious about mixing strains in the same rez.