Don't have charts for any leaner than peak EGT, any operation beyond that is extrapolation, and you are now a test pilot.
actually most engines do, and i have seen the data, and seen all types of engines run LOP.. plenty of data around on LOP ops, so much so, that i doubt anyone would be a test pilot when it comes to LOP in any aircraft..
a test pilot implying that the pilot is flying without any knowledge of what will happen when operating the aircraft in its current setup/conditions..