advice on setup 400w light

okay i have a 400w light and i am putting it in a room that is about 3ft by 10 or`12ft and i want to know how i should set it up.my idea was to use one side of the room and do 14 plants but i want to get the most out if i can.should i put the light in the center and fill the whole room with plants.?the pots i am using are 3gallon pots.and the plants wil be in soil

if you use mylar or something to make your walls as reflective as possible you might get away with using the whole space but more like half would be a more likely situation. a 400w is usually cover about 16sq ft well or 4x4.

would i be better off using 2 400w lights for the amount of space cuz im thinking about buying another light and doing the whole space witch would be like 20-30 plants.

i would go for the 600w if you have the money, but adding another 400w would definatly light that whole space up.

a 400 watt light is a small light and will only cover an area of 3 feet x 3 feet. A 600 watt light will cover 4x4 and 1000 watter 5x5 foot area.You can add a light mover and covera area 8 feet by 3 feet

does the light mover automatically move or do i have to manually do it and how much do they usually run.will i get the same output as using 2 400w lights or close to.because i haVe spent almost all of my money on this and i dont want to spend every last penny i got and wait for my harvest for money.i basically want to spend no more than $140 more and i have found a brand new air cooled 400whps for about 150 with shipping