My view is if you can get all the right temps and a variety of hiding places you'll be fine. GTPs are generally out in the open hiding behind plants, so just put a bunch of plants to let it hide behind. Bigger cages means the snake can also pick whatever exact temperature it wants to help it thermoregulate! I'm sure it will be fine as long as you don't leave it wide open and empty. Snakes do come from the wild where there is no such thing as an enclosure, but there are a variety of hiding places. Over compensate for hiding and your snake won't know the difference.