what numbers are you seeing wot and at part throttle?
what kind of numbers did you see?I used an egt gauge to tune my engine before wb's became popular. I tuned with it for about 15 years. I never had a blown hg or damaged parts while using it.
The problem with an egt is many things will affect the temperature. Placement in the exhaust system as well as timing just to name a few. Timing has a pretty big affect on temps. With reduced timing goes elevated temperatures.