If you can grow 7 plants in 7 gallons under 600watts, I cant see why you couldnt do 1 plant and 45 gallons. To the OP, I believe you are on the right track, even 12/12 fs I get much better results in 10 gallons vs 7 gallons.
My supersoil recipe is not as hot as subs, it's about post #40 in my...