My gut feeling is that if you were getting anything very serious you would
hear it, especially under hard acceleration at moderate or low speeds.
I think leaning it until you get poor throttle response is a good idea
and advancing it until you get pinking likewise, then back both off a bit.

You can evaluate the mixture with a colortune device (you can find them on
the web- (I've lost the link) but not under load unless you have a dyno.

Vacuum leaks or vacuum operated devices will make your idle artificially
lean, especially with carburetors, so that kinda screws things up, especially
for carbs with worn throttle shafts.
--
George Downs, Bartlesville, Oklahoma, Central US