you will get 2/3 of the final height in the flower cycle, if you LST them through veg and as long as you can during flower you can keep prob 2 plants in that cab, allowing 10"X14" per plant and a height of 72" -the space you 400watt hps takes and -12" from the light to tops of branches so take off 16" at least and it gives you a height of 56" from floor to top of grow area and -the height of your pots, around 10" gives you 46" of actual plant height, so final dimensions are 10D"X14W"x46H" per plant with 2 in chamber--------and thats tight squeeze
