hi fellas. i am think of getting myself a 3 ft nft tank. my grow space is 3 ft long 2 ft wide and 6 ft high. i only want to grow one large plant in the tank. under a 400w hps. please could anyone give me a rough idea what type of yeild i would get. and how long should i veg the plant for before going 12/12 many thanks guys look forward to your replys.