In 3 gallon paper pots you can probably fit 8 plants...

or you could go with 1 gallon pots and fit 12 plants

1000watts on a light mover would be ideal.. not a lot of movement maybe only 12- 18 inches...

you will need to exhaust t the closet to keep an ideal temp and steady flow of fresh co2

you will also want to keep the light about 8 - 16 inches from the tops of your plants for maximum yield... which means you will need a fan blowing between the tops of your plants and your lights..

I would go 12 plants with a short veg cycle.. 1000watts with adequate vent... and a mover...

: )

SMB