I would ALWAYS say that a thermostat is a MUST. (We would see far less burns if everyone used them). You stat probe should be placed at the basking spot. Most stats are dimming so will dim or brighten to maintain the temp at that spot. The stat is on the lighting timer to keep the 12 on 12 off schedule. I also place my digital thermometer probes alongside the stat probe to monitor the temp as you can't 100% trust that the temp dial on the stat is going to be accurate. I also have 2 other digital thermometers, 1 at mid point, 1 at coolest point.
If you do need additional heat at night, then use the ceramic heat emitter you have. Unfortunately that will need a second stat and have the temps on that set to a comfortable night time temp. That one would be on a timer for the opposite 12 off 12 on.
I've never needed any additional night time heat. The wife likes the heating on. In fact I have to turn the radiator down in the reptile room or it won't drop enough. Given there's 6 setups in that room, it gets warm in there.
Please make sure there's no chance of the cham getting close enough to any heat source that it can get burnt.
Hope that makes sense.