what size cab for a sun system 7 dual bulb system?

i recently bought a sun system 7 800 watt model.: Sunlight Supply - horticulture and aquarium lighting systems :. Website and was wondering what size cab would be the max for this?for example i know the recomended square footage for a 400w is 4x4 so would there be any difference with this?since its running a 400w mh and a 400w hps would it still be 4x4 or would it be larger?also would it increase the size if i used a conversion bulb or 3k mh bulb?or since both bulbs are in one reflector does it not make a difference?im just trying to figure out if i should keep this or sell it and buy a 600w system.

can anyone help me?i need to build a cab but dont know what size.is 4x4x6 too big for this?

I'm no expert, but from what I have read the more light the better. 4x4x6 would be great but you will likely have heating problems. Maybe with an aircooled fixture and proper cabinet ventilation you would be ok?

If you had it on a light mover it would be great for a 4x8 grow, but if it's stationary treat it as if it were a 600w lamp, which is good for around 5x5. If you're using 4x4 trays I guess that's all you get.