I've Got Both, So Which One Should I Use? 400w or the 600w

I have always done my veg in a 400w tent and then flower in a 600w tent.
But I have recently found my 600w tent empty and was wondering if there is any added bennifit to vegging under 6's then then under 4's?

I'd rather not waste the energy running 6's if there isn't.

there is always a benefit, even if only minor. The question is, would you consider it worthwhile?

I would have to know what the benefit was before I could say whether it would be worth while or not.

But thanks for the help anyways.

More light = more growth.

LOL....did you really ask that fucking question?!? LOL

it is best if u wire them together, so that way u have a 1000 watt light.