Personally I would get a walk in aviary for your macaw. The rule of thumb for cages is the bigger the better. Therefore, an aviary would be best. It will allow him to fly, which could possibly increase his life by 20 years or so because its working and helping more develop his lungs and muscles. The freedom will be wonderful. The only concern is that if he is territorial or skiddish you will have a hard time getting him in there or you may just be attacked anytime you walk in. My idea is for you to walk in there with him and stay in there to show that its' not just his place. However, on the other side, if he is scared he does have a place to hide in there.
Just ask yourself, would you rather rent a room in a house or a whole house?