I don’t control all of the rewards everywhere. Additionally, risk is relative and dynamic, and sometimes subjective but we have no way to even control for that yet.
Our guideline is to best reward the highest risk.
That is normally where I would end this, however since you asked. I usually put Low Sec on top of the list, followed by W-space and/or Null Sec and lastly High Sec. The problem with trying to assess risk for ALL of Null Sec and W-space is that they are so big and players can “own” and protect their areas of space. Lots of factors then play into this like who are your neighbors, what part of Null are you in, how valuable is your area, etc. I think someone once described it to me that Null Sec is like a huge forest. Yes, if you live near the bear and it is hungry, then you are in danger. But if you live in a secluded part, then nobody bothers you. It is difficult to say if that is riskier than Low Sec.