hmmmmm i've read the post again and i think i have the answer......you have lots of head space but very limited depth and width.....practically you need plants that do not branch out a lot, that grow a single large buddy cola.....theoretically you could achieve max yield planting and filling the available space with Chronic from Serious seeds....i've read reports about this strain and apparently it's the one strain that possibly meets your needs....in my last grow i finished 7 ladies grown start to finish into 2 gallon pots....in the end i had root bound but they finished right on time @60 days (indicas)....i would suggest to try and fill the available space with square 3 gallon pots and in there plant a strain that does not branch out a lot, or , fill the space with 1-2 square pots and try to create a sea of green using top44 or k2 or any strain that is good for sea of green technique!!!!!

good luck with your grow

NGOS