FWIW, POHs and operations manuals have been recommending LOP mixtures since the 1930s. Some do not address it in the text but almost all do in the engineering data.
We show this during the APS class.
ALSO, the Wayalla issue would NOT have avoided disaster had it been run full rich. There was a crank issue as well. The engines were NOT run lean. THEY WERE NOT RUN LEAN. They were run "not rich enough" ROP. If one does not grasp the significance of that, one is lacking in the understanding necessary to evaluate the event properly.
The Coroners Inquest came to Ada, Oklahoma, to see this data first hand.
This report is one of the classic examples of an investigation run amuck. They got most of it wrong--according to the HARD DATA.