I entirely agree with Susan. Know that your ig (call him Sam) is deathly afraid of you, and his attacks are defensive. Keep him in a small type vivarium so you can catch him for taming. don't sneak up on him with your hand, just confidently reach in and grab him from the side with authority, pretending that the wild flailing isn't really happening. Press him into your belly with both hands until his lunging stops. The time for that seems to be 30 seconds for all igs. Never, and I mean never, let him escape your grasp by his own will.
I can't tell how much you know already, but your comment about the soon-to-be large enclosure makes me think you might already know a lot. I don''t want to tell you to chew used gum, but this reading is very important. You could never figure it out on your own.