Theres no real answer to your question mate. Theres a lot of things to take in to account. Soil, Hydro, Nutes, Strain and the list goes on. Me personally, I would put 2-4 plants under a 400w
I dont really undersatand what your planning on doing here. Could you run through it with me?im running soil, fox farm line/soil and id be vegging for a month and a half would you say atlesat 3-4 oz every 2 months?