Stuck on a light/growspace/plants problem.

Right now I have 6 plants and growspace ~1,5m2 = 50sqfeet.

And I need help for light. Which to choose:

1) 250W HPS TS, 35000 lumens, growing area 0,9m2

or

2) 400W HPS TS, 60000 lumens, growing area 1,2m2

Could I grow good yield with 250W in my growspace or I need 400W light? Will use light with reflector!

Thanks a lot for your help,

Mari.