I'm definitely with Organoman here... I see you've just pitched some autoflowers and if you decide to go this route, you'll be pitching these as well. I start all my autoflowers (and so far, they're the only things I grow) in ProMixHP which has zippitydodah (zero) nutrients because I want to control the what, the when and the how much of any nutes they get... And autoflowers do not like nor do they need any nutrients at all for the first couple weeks of their life.... and when they ARE introduced to the plant, I start them out with 1/4 strength to make sure they're going to be tolerated.
So, as far as your plan is concerned, I'm not in favor at all... sorry!
Good luck