If you have not grown before, may I suggest you try your hand on a couple of small grows first before going into it gung-ho, say a 4X4 tent initially with a good LED grow light that will provide adequate coverage, a couple of oscillating fans and carbon filter with a 4" or 6" fan. There are a lot of potential problems that can go wrong, even from one grow to the next, and some people who have a keen interest soon realize that despite how much they like smoking it but don't want the hassle after realizing what can go wrong. Once you see what is required on your part for those 4, you will be better able to decide if you want to continue, and then figure out how much space your going to use. may seem slower than what you might want initially, but in the long run it could save you a lot of grief...and money. However I do envy the space you have, as I operate a small 1 meter x 2 meter grow space in a room 7' X 7' closed/ hybrid set up, with an air conditioner, and CO2, mainly because I have extreme environmental changes and growing year round presents some challenges at different times of the year with an open grow room system. First you learn to grow, then you grow