If you want to learn more about 1911 gunsmithing, maybe even enough to build a 1911, I can help with the sources of information that were important to me.

No pistol round is “best for self-defense;” that distinction must be reserved for rifle rounds. Having said that, I think the available data supports the idea that, for pistols at least, the 9mm round is adequate for self-defense, but not any better than that.