I don't think your cage is too large, as long as there's plenty of hiding opportunity. There's really no way for us to tell you how long it will be before your
snake feels settled in his new surroundings: they don't understand how their world just changed & it's frightening to them, but just give him time to get
used to the changes...hopefully it won't be too much longer. It's not only the cage that's different, but the activity around him that he's aware of.