first grow box questions plus walkthrough

I am going to be doing a walk through of my build. I've done 3 grows but were all closet. Plan to be growing two plants at a time with cfls for now. My first grow in the box will be an auto grow. Dimensions of the cab will be 5' tall, 3' wide and 16' deep. I am a little worried about the depth?

Not for two plants. My clone/mother area is 18" and I have room to spare.

You may have to move branches around if the strain you'll be growing happens to be overly bushy. Also, just keep the CFLs as close as possible.

-spek