im building a new grow box because my other one was too big. would a grow space about 4 feet tall and 2 x 2 give me enough space for 4 lowryder2's or 2 burmese kush plants?
I initially had the same problem when I lived in my last place (it was show box size ) my box took up quarter of the bedroom.
IMHO 4ft high is cool even with a hid light as long as u have good venting although u may need to top your plant/s prior to flowering.
Depending on strain the 2x2 width and depth should be ok and if not its nothing a little prunning cant cure. Good luck.