Personally I put the sensor in the warm end to ensure the maximum temperature is controlled. A night time drop is preferred but not essential. By knocking the heating off completely the snake can get too cold if the room does not have heating. I'd leave it on. Use a digital thermometer to get the temperature right - don't rely on the settings on the thermostat.
Breeding group (6 adults) of Variable Kingsnakes for sale plus various American Ratsnakes and T- Albino Chinese Chinese Beauties. Contact me for details.