A cistern with a fixed amount of water in it will produce the same amount of condensation irrespective of the thickness of the material given that the water temperature in the cistern and the air temperature and relative humidity are the same..what varies is the time taken to produce the quantity of condensate and the water to reach equal temperature with the rest of the room.
In short, thicker clay will slow the production condensation down slightly but condensation will be formed for a longer period of time
So all cisterns will eventually condensate will they
As a teaser: the cold water main coming in is -1 Degrees
You are waffling & uneducated. Your above statement was a load of old cr*ap as well, as for JohnD, Don`t make me laugh.