In the aircraft I'm familiar with it isn't a procedure to lean based on CHT readings. Most flight manuals dictate mixture settings according to either fuel flow for a given power setting or a mixture setting which gives either peak EGT, 50 degrees rich, 125 degrees rich etc... (have a look at the J. Deakin articles to make up your own mind whether this is really the best method).
The EGT gauge gives a much more immediate indication of what is actually happening during combustion (heating a volume of air compared to a volume of metal).
During a sustained climb CHTs should be monitored, and if approaching the upper limits perhaps adopt a higher climb speed to get more air flowing through the engine. As well as adjusting airspeed cowl flaps are used to maintain acceptable CHTs and are typically open on the ground, during takeoff and climb. I usually close the cowl flaps approaching top of climb providing CHTs are at acceptable levels.
During cruise CHTs should also be monitored and power settings or cowl flaps adjusted if they start getting too high (typically around 500 degrees F).