Just read this... Awesome! Well 9 sounds perfect but I got some tester seeds in a 10 pack so I'm popping all those and will have a thread posted soon.I was in a 4x8 and did 4 in each 4x4 square and it was perfect in 3 gallon pots.
This time around I'm doing 9 (in each 4x4 square) just cause I wanted a shorter veg time.
I'd probley go with 9 and veg them to like a foot or foot and a half cause they'll almost double after stretch end up with 9 solid little 3 foot bushes.
so 10 for flowering will be good i think if properly trained and spaced.