But Andrew, how do you know where on the lean curve each of the cylinders on these engines is running now?
I don't, which is one reason why I said it's a gamble. You were the one lamenting that there weren't needles and jets to go leaner (although I'm sure there are).
Also, you would be departing from the configurations which have at least had extensive testing and use to something which has probably had very little.
MAYBE it has been shown that you can't damage a Continental/Lycoming by being too lean. Even if true I don't believe that applies to all engines.