Hi,
Am I reading that right? 4 foot by 3 foot by six foot !!!!high? That is going to be the worst nightmare you ever encountered trying to keep temps and humidity right.
Just having something up high isn't a good enough protection to prevent burns either to be honest - I would try and find some way to safely guard it if your determined to stick with that enclosure. For the life of me I can't think why you'd want to do that to yourself though.
Have a look round the site for peoples experiences on what they had to do with large fishtanks to make it work and contrast it with what it takes for a good tub setup.
But yes I would try and find some way of getting the cool end temps up. I afraid I can't remember what size is your bp just now?
dr del