Engine Temp. Gauge Issues

Wild needle swings is a symptom of failing mechanical limiter. I never tried to figure out exactly why this shows more in the temp gauge than in the fuel gauge. Resistance the sender is providing? Length of the circuit? Both? I know current takes the path of least resistance.
In the 73 we had... Gauges worked perfect from cold start. Turn switch off, go in and out of the store, turn switch on again and temp needle would race to high as it could go then slowly fall back to normal reading. No strange behavior in the fuel gauge. Solid state instrument voltage regulator cured it. New mechanical limiter would have cured it. I choose to go solid state.