Argus can easily get 7ft and need a lot of room for their high energy levels. Dumeril's/brown roughnecks, black roughnecks, blue tails, mangroves, and peach throats all stay in the 3-5ft range and are easy to deal with. They all will calm down with gentle handling and just getting use to you. These species also don't really need a full room to be happy either. I'v got a arg b&w tegu that is about 3 1/2 ft and have been preparing to get a peach throat. The fastest way to calm any tegu or monitor is to take a towel or shirt and have it reak of your scent and put it in the enclosure. Refreash the scent every week and the lizard will think you are no threat.