When using modern oils at leaner mix ratios it is worth remembering that fuel is metered into our engines by VOLUME.
So if there is less oil per unit volume, then there must be more fuel.
Or to put it another way running a lean mix will also run a rich mix.
So when you start using a leaner mix, carefully check the plug for build up at regular intervals.
Carbon on the plug is no big deal, but a rich mix carbo build up in the cylinder can break free and score the bore.
Thus on chainsaws I back off the fuel jets a touch till they are just barely on the rich side of balance.