We are using MAX 31855 Quad K type shields on breakouts for thermocouple input and have compensation lead that runs to quartz insulated thermocouples that are physically welded to the vessel. Right now, each IOT-800 has one shield, so we have the ability to read 4 thermocouples, but are only using one for controlling the heater, although we do have additional thermocouples hooked up to see what the temperature is around the heater on some units.
The way we have this implemented is overly complicated and a bit of a mess to be honest.