I have absolutely no intention of instructing anyone to ignore your advice Islander2.
"That engineers and other pilots alike advise operating the engine in the worst possible way isn't of much help."
Again Islander2, you are completely dismissing other people's theories on the strength of your own opinion. You clearly have more technical knowledge than I, but you crudely assume the others I mention don't know what they are talking about. It is you that has interpreted "slightly" rich of peak to mean less than 100 degrees richer.
Disagreement is part of healthy debate; dismissal is self-righteous.
huv I would suggest you consider Islander2's well explained theories and compare with the wealth of knowledge on piperowner.org. They may well be the same.