Temp Problem on 1992 Honda Civic

I have a 92 Honda civic 4 banger stick shift with 150k miles on it. Last year the car was overheating and we fixed the head gasket and machined the head. This year I noticed that the temp gauge is very slow to move. When I drive the car the most the gauge moves is to the lower quarter of the cool side. Now most cars run right in the middle of hot and cold. I store this car for the winters here in Chicago and I noticed this problem since I took it out of storage about 3 weeks ago. I did replace the radiator a week ago, but the problem was before that. I am worried that something is wrong. I would think that it is the temp. Sensor because the gauge still moves a little. I am just worried that the car might over heat. The service engine light is on for the cam positioning sensor and I don't want to replace that so I will not know if the car is overheating unless there is a temp light. Does anyone know what I should do and where the temp sensor is located? Also, if I run the car for a while and the engine is hot what temp. Should the car run at? Because I can stick a temp probe in the radiator fluid to see what temp it is and if the gauge is reading it properly. Thanks for any help