That lil guy is awsome. My iguana was 5 1/2 feet before I had to have his tail amputtated

(bad blood circulation. He's 18 yrs old. There are a few pics of him on this site) As for keeping him caged I would start getting him used to roaming the house and learning his limits (rules) Mine hasn't been in a cage in 10 years and he's paper trained and everything. I'm a huge fan of big lizards and think its really cool when some1 ACTUALLY takes care of one. Make sure you handle him ALL the time and he will stay being a great pet. Reps to you!
Edit-Make sure you cut his claws with a dremel tool. Cuz they can rip the hell outta yoru skin