I need help ventilation question and number of plant question

this is my first grow and i am building a grow box 4 feet long 3 feet wide and 6 feet tall im not sure how much ventalation i need will two pc fans one going in one going out be enough and where should i place the fans at the top or bottom. my other question is i have been reading that your plants need a square foot for growing meaning i can get 12 plants in my grow box but i have read something about less plants that are busier might get more yield . im using a 1kw HPS light for maximum yield will i get bigger yield with with the sea of green method or say 8 plants with more room to get fatter ?? allso im thinking about going with either white widow, white rhino or snow white which in your opition would be the best strain with the strongest thc content and the largest yielder and for the plant to not out grow my grow box ?? thank you very much for any help at all!!! peace

could someone please help me answer any of my questions its finding its way to the bottom of the thread list very quickly with zero replies thank you for any input

Is your light hood air cooled? For that small of area it is going to have to be. Vent the heat from the light to outside of your box. You only have 72 cubic feet inside that box, it is going to get hot very fast and easy. You should be changeing out the air in that box about once ever three to five minutes. You want the fan that is putting air inside the box to be down low to pick up the cool air, and the fan inside blowing outto be up high to pick up the warmiest air. Plus put a fan inside to keep the air moving around. So NO, a fan from your computer tower will not work. At least that is what I take you ment by PC Fan.
Myself, I do not like to crowd my plants. I would only place 6 plants at the most in that box. As for which strain. This being your first crop, you should go with an Easy to grow indica. Most everyone over love's their first crop or two.

1kw is too much in there. i'm thinkin that both area and height are small. if you can make it bigger it will be great like 5x4 or 5x5 area. you can also make it higher and do tall plants. SOG is not suitable in there but then growin tall plants in 6ft high under 1k also is not rright.

I have to agree with Zem. That 1K light is to much for that small of an area. But if you use a High Volume Votex blower fan to cool that light you should be ok. But these Vortex fans are very costly.