I put my cham in a smaller cage outside. He's usually ok when I move him out but can be pissy when I go to move him back in. I know he eats better outside than inside.
I also hang the cage so he's well above the ground.
I feel as if you should be fine, I have seen people put their chams in Bird cages that are tinier than that.
He may be stressed out at first due to the new and strange environment, although if he enjoys it he will be less stressed. I would just keep an eye on him.
I also plan to make a flowerpot cage for my Cham so he can bask in the sun in the summer.