Just remember that the car's engine is not flesh and blood. It will run best at a reasonable temperature. Even "Sweetie" Tiny.
I run a 180 in all my old cars. That seems a good temperature for heating up the engine on a cold day, getting the oil to its most efficient operating level, and not causing the coolant to expand beyond escape level.
A 160 degree thermostat seems to work just fine for most of you but in the winter/cold conditions, that may be insufficient. Your call.
As long as there is water circulating in the engine. you're not likely to damage it none, When it boils over and looses coolant then is when trouble arrives. Lower quantity of coolant. especially below the water pumps ability to circulate it will likely cause damage.
Best I recall, steam will not register on the heat probe so watch out for that condition. You may crack the block or head.
Relatively speaking you can run an engine at a temperature way below what is efficient for it. I recommend a thermostat. Whatever the temp you choose.
Your engine will thank you for running it at 180-190 degrees.
I agree with Chipper on this issue. After fully open the thermostat is on little help in establishing the running temperature of the engine.
Best and my two cents worth.
Charlie

Usually you want to add coolant while the engine is idling, especially when it is overheated.. Best is to wait until it has cooled way down. Pressure caps were a great help to automobile engines.
Water boils at 212 F at sea level. Some of you live way above that so keep it in mind.