I have to disagree, with this statement. I personally feel a showcase cage provides the most efficient heating,often has a real thermal gradient as well. and easily obtainable humidity without having to sacrifice ventilation.
I do agree that it sounds like yours is in need of hiding space and I would second the need for well fitting hides. Find something that is big enough for it to fit in but not much bigger than that opaque and solid. Place a few in on the hot spot and cool area and perhaps on in the middle and clutter it up some fake plants work wonders that way and then let it be no checking not poking about just quiet and stable for a few days then check to see where he is. They are timid and need time to adjust.
How is your husbandry? (temps and humidity?)