Why does nobody give advice? Simply because the vast majority don't know!
How do you lean properly without the benefit of full engine monitoring kit? Follow the advice already given by Lycoming.
Lots of people will through up their arms and say "That's not what Deakin says...." but to be honest I'm not convinced about all of it.
I was involved with data collection on IC engines of all kinds from my days at Uni, and the results can be skewed in all sorts of ways. Especially if the customer has something to gain from a certain conclusion. i.e all the data comes from GAMI and they sell the stuff because Lycoming obviously have no idea what they are doing...... (According to these comments and results anyway.)
So, until someone comes up with a definative source on what to do on a bog-standard engine, then the manual is all we poor saps have to go on. Since I rarely see engines going pop or use too much fuel, then I'm certain the standard procedures seem to work O.K.