12 plants under 2000watts. How many watts for veg?

[iDatsyuk]

I have a 10.5 x 8.5 x 8.5 spare room that I planned on flowering 12 plants in. 2000 watts. 2 XXXL magnum reflectors.

I have a 4x7x6.5 tent that I wanted to veg in. How many watts from an MH bulb would I need to veg 12 plants? The tent might be a little big, but I can split it with panda film. Would I need anything more than just passive intake? Can someone at least answer the how many watts of MH I would need for the 12 and then possibly link me to a good step by step veg guide that includes ventilation info. I'm brand new to this but I have what I need. Just need some good advice.

Thanks a lot!!

 

[iDatsyuk]

I was thinking shrink the tent to 4x4 and get a 400 or 600 watt MH setup.

When it comes to ventilation for veg, I'm still not sure. Just a regular oscillating fan?

 

[Antics]

The most complete guide I know of: How to Grow Marijuana Everything You Need to Know

Good topic on lighting: Calculating square footage vs. lights needed

Oscillating fan 24/7 for circulation.
Ventilation fan 24/7 for keeping fresh air coming in at all times.

Vantilation fan + Carbon filter if odor will be a problem.