Moral minds

Q1: Should we all have the same moral code?

Q2: What moral system should I follow?
- The one I have been taught in the school and by my family?
- The one that is closest to human nature?
- The one that is closer to my nature?
- One that is good for me?
- One that is good for the many?

Q3: How do I decide? Won't my decision be one of judgment? Won't this judgment flow from my moral faculty?