yes the humidity will be very good. If you want to get a "tub" for an adult I would recommend a 35q tub the sterilite dimensions are 24.5" L by 16.25" W by 7.5"H I recommend also to get one with a locking lid because you dont have to use clamps to know the tub is secure.

http://www.sterilite.com/SelectProdu...=180&section=1
the above link is an example of one I have that works great for me.

I will say I had to drill holes for ventilation and humidity control ( it was too high) but the tub took less time to set up and works so much better than the tank we had for our first girl. Just be sure to get a UTH with the proper temps and regulation, hides and a water bowl and decide on a substrate and the tub will maintain husbandry like a champ.