the seed company adds are for yield per metre squared, ie 500 grams per metre squared , usually grown sea of green method ie 100 plants growing just 5 grams a plant in a metre squared ,and usually using co2 injection and the best of lighting , yields of one gram per watt of lighting are possible with the correct techniques ,ie hydroponics ,topping,training and sea of green , some guys even pull these yields in organic soil.......(vancouver sealed rooms)
1000watts should be able to grow you more stash than you ever need