Also dutch, I have (and read) several grow guides. Todd McCormick's, the 4ed Cannabis grow bible, and a few others that are more obscure. I'm less worried about growing the actual cannabis, and more worried with constructing a box with quality lighting. I was going to buy a 400w HPS light and work from there, until i read the light making guide that i mentioned earlier. With making my own light i'd free up some cash, and of course have the ability to grow more.

I just don't want to go overboard and have too much lighting in too small of a space, or have too little in too big of a space.
I may be worrying a bit too much.