The usual temperature controls on old steam systems are the airvents on the side of the radiator. These worked by metering the air leaving the radiator, delaying steam entering the radiators according to the heat need in the room. I am interested to know the type of temperature controls you have on your system. There were diaphragms in some two-pipe system hand valves and some traps on other two-pipe systems that would regulate the heat.
Without information of that nature, try this exercise - tell me how my heating system works.