to sensitive means it cycles on and off all the time? or the temp swing between on and off is too much?
I read from factory it has a 2 deg temp swing. (most homes are set to 1 deg) you can set the temperature differential from the front buttons.
see Temperature Differential page 9
Here is manual
But it appears this thermostat has 3 wires. 12V positive and negative, plus 1 communication wire that goes to AC. than your heater is also wired to AC where the AC controls heater based in input from thermostat. so your not going to replace it with a common home thermo.