Thanks for this thread, I'm trying to figure out the exact same stuff. I've been using the same room to flower and veg in and I want to speed up the process so I'm putting up another room too. I root clones in a cloner, then want to move them to a spot to veg until they're about 18" tall. Figuring out exactly what we need has been a pain. I've got plenty of room, just can't figure out how to share ventilation in the rooms to save money, but I guess we can't.