The big picture answer Duffy, is there is no answer. The internet will make doubly sure of that. They've moved towards what works best largely through trial and error, and not science.
The science attempted in the public realm is sketchy at best as it's usually trying to hawk a product, and even some mil stuff is terrible. Reference the Thompson-LaGarde pistol tests of the early 1900's. Buffoonery and bad science at its best, creating a myth that has endured for a century that the .45ACP contains some form of magical "stopping power". It is in actuality identical to just about any other pistol cartridge, and worse than a good few.
One rule that is undeniable is speed kills, it's the whole principle of ballistic wounds. The next rule that is undeniable is that of diminishing returns. It seems that curve starts to level off around 2,000fps, higher helps, but not always, and that's just my non-scientific opinion which is also likely hogwash. Stopping power is more sorcery than science, and often misguided, big bullets only seem to have more on bigger animals in my experience, a .243 works as well as my .375 on deer, also my likely delusional take on things. Having been married to TSXs and the like, then shooting Federal Blue box with excellent results as well on very big things, my opinions have softened severely. I've shot an awful lot of things with an awful lot of bullets, they all died.
Finally, the third rule; Nothing good nor productive will come of this thread. It's all opinions.
