It's interesting that everybody rates Athena nutrients so highly and there formulation is close to the Lucas ratio. I wonder how much of Athena's success is to do with it simply being a good ratio of nutrients.
I am trying high EC right now vegging at 2.6 (0.7 starting EC) and will try to exceed 3.0 in flower. Floraflex also recommend these crazy high EC for LED growing due to the low transpiration. They have different target ECs for different lighting types. But it's all so hard to say because everyone's water is different, everyone's ambient temps RH and air flow are different, different lights everything plays a role.