I run a ford 170 thermostat in mine, keeps trans temp around 165-170 for highway. City driving will see the trans run around 170-175. Thermostat temps range between 165-195 (165 is in down hill sections where I’m coasting and the 195 is when I come off the throttle and it spikes briefly before cooling off rapidly) during mountain driving where the engine is using a lot of boost. Engine coolant typically stays around 180-185 on relatively level ground.
On any thermostat you’ll find that where the temp sensor is, it will read about 10 degrees hotter than the number stamped on the thermostat. The trans will read almost dead-on what the thermostat is rated at.