I went from no thermostat to a 160* thermostat in my TA and it seemed to consistently run cooler on the street, but I also changed the radiator cap to a higher pressure unit at the same time so I honestly don’t know which helped. I hit 200*-205* on the street briefly before the change with no thermostat. Got up to 185* with the updated 160* stuff. I’m running a meziere pump as well. It’s funny this thread came up because I was just thinking about pulling water from the back of the heads like this first set-up posted to see if it would help.
