87 C or 92 C dependant on engine type ,early non injected units are happy to run cold but later injected units need to run at there optimum temperature. The issue with rad fan duty cycle can be down to year build. However, be careful not to be sucked down the 'iv'e got to stop the rad fan running' road because you won't.
+8's run HOT, as long as your fan only cuts in when you stop I would not worry too much. However, always carry a spare rad fan relay in the car, the duty cycle on these is very high, as is the failure rate.If you dont know the relay Cereal or Oldtimers can help.