Baby snake care

Hey all, need some advice on rainbow boa care. I've had ball pythons, corn and king snakes before so general care I get. From what I've read humidity is key, so I was planning on getting a 4ft viv with a humidifier and a heating lamp but I'm worried that might be too big for a juvie. I guess my question is one is it too big and 2 if it is do you have any suggestions on the kind of setup I should get for a juvie rainbow