Given the fact that EGT for a particualr engine/exhaust will vary slightly from other identical engines as a function of  "where the EGT sensor is placed ", and stating at the start that we are talking about "cruise" power settings - not "full throttle at sea level" (in other words, we are, by definition only talking about leaning at a lower power setting, with proper timing and proper octane, where there is ZERO possibility of detonation) isn't it true that if one adjusts mixture from rich to lean, that the EGT will "peak" at "best fuel-air ratio" for complete combustion, and that max power will be achieved by richening a bit from that (richen until you get max RPM for that immediate flight condition) which will result in a slight drop in EGT?  Then, if one leans back to "peak" and then continues to lean, one will get "better economy", and, again, EGT will decrease from what it was at "peak".

It seems you understand correctly.

  From reading of what others have said, one can lean past "peak" maybe 50 degrees and have a safe, economical cruise setting, maybe taking a slight increase in throttel or manifold pressure to keep HP up to what you want to cruise at.

-        The old Air Force BIG radial engines used to cruise at 80 degrees lean of peak for long flights requiring max economy.

I think you’ll find that you can go to more than 50F lean to advantage with a rotary on easy cruise (ask Tracy), and I found peak power to be more like 100 F rich of peak.

So, I believe there is no such thing as "EGT too high".  There is only "peak EGT", whatever it is for  your installation.

High EGT can be symptomatic off other problems; incorrect timing is one.  You’d also like to limit EGT to something less than about 1700 F to avoid shortening the life of your exhaust system.

Al