I recommend CHE for BP's. The less light the better for them, at night especially.
CHE will raise the ambient temp well and you can still use UTH for belly heat.
As mentioned, make sure you are getting accurate temp readings by using a temp gun.
Also, all heating devices/heat sources, must be regulated and controlled by thermostat.
Humidity is tough in a glass tank. I'll let others chime in on that more as I hated glass tanks for that reason (and also ease in temp control and temp gradient is easier in an enclosed tank as well).
When you upgrade as your BP gets bigger, I would greatly consider an enclosed PVC tank.
I have Boaphile tanks and love them. Many people here like Animal Plastics (AP) as well. You can read up in the caging forum, or feel free to ask for advice.