Practical experience here... for white tails, anything even close to .45 long will do it.
My experience comes from using a Freedom Arms 71/2 inch barrel with hot 300 grain XTP magnums. Knocked em flat. So did 240 grain. So did downloading them.
So did “ruger only” .45 colt loads out of a 5 1/2” Blackhawk. Knocked whitetails flat.
So did 18.5 grains of 2400 under a Keith style swc... but instead of punching through the lungs, hit them in the neck or shoulder. I used that same load with 240 grain xtp s.
Factory .44 magnum stuff worked just fine for my dad out of his Blackhawk.
I am really glad I had a chance to shoot .454 Casull when I was younger and tougher and had the fantasy of going to Africa to visit my sister and brother in law. They managed a game preserve. They decided to have kids, and came back to the states... just as well.
Explore some loads, don’t feel you need to hit a white tail with an atomic bomb. 18.5 grains of 2400 and a 240 grain xtp will do you well and is pleasant to shoot. A cream puff compared to many of the Casull loads I’ve detonated through deer.
Enjoy it, even if it’s a fantasy of shooting elk or moose or hogs or African buffalo, it’s one I enjoyed thinking about and working up monster big bore hand cannon loads for. It was fun to annoy the Glock kids at the outdoor range with loads that required maximum earmuffs AND ear plugs both!