I also want to add that if you set up your engine to run lean, be careful because detonation is very bad for an engine. there is a reason it is set up for the air/fuel ratio that it has. it could probably go leaner but if you go too lean, it could do serious, permanent, and potentially catastrophic damage to your engine.
I am not saying not to experiment but keep that in mind.
Be the change you wish to see in the world