Hey top dog.
I stand under correction here as to wattage. But I use a single 250watt ceramic heat emitter on a dimmer, as well as four of the largest heating pads at the bottom, also controlled by the main thermostat. Two water bowls on each side of the tank, one just off the heating pads and one on the cooler side. I had been experimenting with different ways, but this seemed to be the most sufficient and accurate for me with regards to both the temp ad humidity. The ceramic heat emitter has been running for four years
I know of a few guys who use wall panel heaters in there big burms walk in cages. I cant really comment as to how well they work, because every time they shed, they arent 100% and their water bowls are baths. Im also a firm believer of some source of heat form the bottom. (just one of my little weird ways) I feel this aids in digestion. In one instance, the last time we moved the 5m male burm out of his tank to feed he felt nice and warm on top of his back, but started getting cooler down his sides and cold underneath. And this is one from the panel heated room.
Those ceramic heat emitters are amazing as to controlling the ambient temps in the bigger tanks. Good luck.
LIFES A .........