good start there man, 600w will be such a huge difference you will be amazed i promise ;)
best advice i can give is READ READ READ, and just when you think you have a good idea READ MORE...keep in mind that you can ask 10 growers the same question and get 10 different answers. your knowledge will come with plain old trial and error and eventually youll get dialed in on whats best for you...
i would recommend also looking into compost teas and also mixing your own soil, plants love this :) organics is fun so good luck and careful what you give your plants ;)
BTW redman is right, there are better nutes than fox farms, look into
advanced nutrients like he suggested (i am using iguana juice now) another good one is
general organics line (i recommend the "go box", it has all you need :) )