400W's can do wonders, but I don't want to get anyones hopes up to high, but on OG many life times ago a fellow pulled a LB from a 400W with a 16 plant SOG type set up hand watering, but he was called a master by most. Just don't knock the 400W.
Also, Jamstagader right here on our board pulled a LB off a 400W with 200W's CFL side lighting in a scrog in a cabinet grow.
Adieu