in a 4x4 tent i was averaging around 500-600 grams of dry nug but that was with a 1000watt air cooled hps light, may i ask why you want too go so small?
do you have space for a 4x4 tent?
if your growing for 2 people i dont think a 2x2 grow tent will cut it.
my 2 cents buy the 3x3 but if you...