It is almost impossible to hurt most standard carburated normally aspirated small flat engines by overleaning, especially below the 75 percent power setting. They will start to run rough due to poor fuel distribution before you are lean enough to hurt anything. So if you lean untill roughness and enrich untill smooth (plus maybe enrich just a touch more for good luck )
you will be fine. You will also get quite a noticable increase in power especially at higher altitudes. IMO the real danger is overheating in long climbs at low airspeeds. Since most little airplanes have
engine instrumentation you won't know you have cooked the engine untill the expensive repair bills start
This is especially true with the Continental 0-470 series. My Flying club had a 182. It required replacement of all the cylinders twice
to make the 2000 hour TBO. Most cylinders removed displayed signs of overheating and or shock cooling cracks.