Joe, They will go faster at that price, versus $1000. I think which ever one you like the best, and feel the most connection with, is the one for you. I think you could get away with that small of a cage for a short time, but it's best to get a bigger one before too long. Changes are sometimes hard for some greys, so I wouldn't wait too long, especially if it will be in it all day.
As long as it is eating now, rejecting food shouldn't be an issue, just use the same food it is used to right now. You can change later if that's what you decide to do. It might slow down it's food intake the first few days, while it adjusts, but shouldn't stop eating completely, if it does, see a vet asap.
Best of luck, and keep us up to date!! :)