How to grow OG KUSH

I was thinking of growing some white widow before because ads say its everybody's favorite weed, researched it and everything. Then I talked to some hookups and they said most people don't like the full body high just the mental high, so i decided I wanna go wit kush. But I got alot of questions, i'm gunna be growing it in my attic which seems perfect for it. But how much space would kush take up fully grown? Where are some legit seeds I can buy, and tell me if you've boughten from that company before. And if you can, just give me general tips about growing.