[Healeys] Thermostat Choices

[Kenneth Fleming]

I recall reading in the past a thread discussing the different options for thermostats for BJ8`s. Currently there are several options that will work and some of the choice is based on personal preference, home climate, antifreeze mixture etc.  I have had over the years several different temperature thermostats in my car. 
With a 160,180,and 190 degree thermostat what should I expect my gauge to read  on each if assuming it is calibrated correct? Is this degree designation an exact number? (forgot not much is exact with a Healey) Also, with running a160 degree year round could it potentially run the car to cold in colder months and do any damage to the engine? Our winters are not to harsh or long in the southeast, but I do drive year round.
I have had the sleeved type with success recently from Moss purchased a few years back. (NFI)
If this subject has been thoroughly discussed in the recent past, I would appreciate someone directing me to it in the archives.

Ken