Too Hot

I’m still tuning the six pack, learning what it likes. AF at cruise (55mph@2600 RPM) is around 12.7:1. Goes very lean at WOT before outers start to add fuel, trying to remedy that.
Plugs are sooty, dry, not oily. Plugs are Champion RC14YC, oil is Amsoil ZRod 10W30 full synthetic. Fuel is 90 octane at the pump.