I the gauge is anything like the Gen 3s, you can take the needle off and put it where you want.
The way I check my t-stat, to get the most accurate reading of operating temperature, is to take the upper radiator hose off and insert a know accurate thermometer in the hose. Then start the engine and watch as the t-stat opens and closes. I do this when flushing the system and keep it full of water with a water hose feeding the radiator.