Kali Mist grow - Some questions

Hi. I'll start a new project soon - Kali Mist.

I wonder how many Kali Mist plants to grow under 400W HPS?
One option is to put 6 plants in 2,5 gallons pots and the other is to put 4 plants in slightly bigger pots (3-4 gallons).

I don't plan to do LST or HST. As I know Kali Mist is a tall plant and is not as bushy as an Indica plant.
The height of the grow room is about 8 foot. The width of the room is not a problem, because I'll make it as wide as needed.

Any advices and suggestions will be appreciated. Thanks.

bump, bump

I'm concerned that if I use larger pots the Kali's will grow too tall and the light of the 400W HPS will not be enough for the lower parts of the plants.