I finished Hell difficulty with MP 10, but I can't do Inferno on MP 10, so at what MP level am I better off farming Act I Inferno, than Act IV Hell on MP 10?

The same goes for the different Acts in Inferno, what MP levels are equivalent between the different Acts.

Equivalence in respect to

- loot drop rate per item level
- gold drop rate per enemy killed
- and XP per enemy killed