2x4 is a great setup....I have a HydroHut Silver Addition that is actually 2.5'x4.5'. I used to grow 5-6 plants in it until I got smart and now get the same yield with only 2 plants that fill it up very well. I use 2 - ProSource 180W jumbo LED's and they do very well in this tent.....I've run 400W HPS in it too but had more heat issues thus higher vent fan speeds. Either way you can yield at least 8oz in that space if not more using advanced SCROG methods. My zippers still work too.