Propagating Tent Requirements

I am purchasing a 2' x 2' x 3' tent for propagating seedlings and clones. http://amzn.to/w1KQTm

How much exhaust fan do i need to properly ventilate this setup? How much would my results likely differ between a 4 bulb, 8000 lumen, T5 setup versus a 6 bulb, 12000 lumen one?

Thanks.