I did similar in my 1984 & 85 300D's, but don't know if they translate to your car. I posted w/ the resistances vs temperature I found in a search, plus my measurements w/ IR gun and substitution resistors. Yes, the sensors for the dash gage and EGR have much different responses.

Recently I pulled up my post because dealing with an apparent overheating in my 1985. It started running ~100 C on the dash and the IR Gun confirms "too hot". Changing the T-stat didn't help, nor looking for debris in all hoses, and I did purge out all air. Now suspecting either the water pump impeller separated or a crack in the head. I did get flow from the top hose if I rev'ed it, but not while idling, which didn't seem quite right. I'll sure do many more tests before I finger the head. Finally, the oil cooler top tube doesn't get near as hot as the bottom, so it doesn't seem to be flowing much. Perhaps something happened when I last changed the oil filter.

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1984 & 1985 CA 300D's
1964 & 65 Mopar's - Valiant, Dart, Newport
1996 & 2002 Chrysler minivans