I just picked up a 6L humidifier just trying to gauge what kind of increase or size I need. I’m thinking with how small this one is I’ll need a shit load lol.I think if I was going to do a tent that sized with an 8" fan I'd go with venting outdoors. You're going to be moving a crap load of air and with the door closed it's going to have no place to go. I'd rig up a dryer vent cover looking deal or gut a broken AC unit to make it look stealthy and put a good filter on the end to ensure no super critters can get upstream during a power outage. Then just tend to any light leak issues if that's a concern and all the hot air is going out of the room. I'd be concerned about the 30% humidity though. You'll need a decent sized humidifier to bring that up to an acceptable range for the room. I have a medium sized one just outside my passive intake and it can increase ambient humidity about 15-20% at best. That's for a 4*4. Trying to humidify a much larger tent will take a decent sized unit or multiple small units at each intake. You're looking for 55-65% humidity in veg, even higher with babies, so 30% is going to be tough.