I have used a Chapuis 9,3x74R double for the past 6 years. It has become one of my favorite rifles and calibres. My 9,3 is scoped.
I have used the 45/70 longer. With Garrett Hammer heads, Buffalo Bore factory loads or equivelent handloads it is very powerful. My brother had a 45/70 Pederosoli for a while. Information provided by the factory stated that the rifle was safe with any load suitable for the Marlin Lever Action. My brothers rifle shot very well with such loads.
Either rifle would be good for the hunts you describe.