Lots of red flags. Rather than making assumptions, are these sockets and area the bulbs would go protected in any way? I'm really scared at the potential problems with what you are describing. Also, how is this wood finished? That is another potential issue.
Regardless of that, RHP is a superior solution for heating large BP enclosures because of the stability of heat and less of a drying effect than CHE.
UTH doesn't work well in large enclosures, especially when the bottom of the enclosure is quite thick. Without proper ventilation underneath, it's a potential fire hazard as well.
If you have pictures of the enclosure that would help a lot in making suggestions, but depending how things already are in this new enclosure, this may be a very unsuitable enclosure for a BP.