A zero to hero hasn`t got a chance in hell of getting the aircraft on the ground single crew after 10 sectors if its there first job and 200 hours total time.
I don`t think of the extra FO as a safety feature more of a paper work instructor. Which to be honest they are alot better than me at. That is if we have spare one. If not I am on my jac jones with more work load than single crewing it. But still I get alot of job satisfaction from seeing them improve and develop.