I was going to get a 8x4 grow tent with 2 p600 led grow lights but then someone told me I would have more room in a 6.5x6.5 grow tent I am trying to grow 12 big plants will there be enough room in the 8x4 or should I go with the 6.5x6.5 and if I go with the 6.5 should I still use the same lights...