I don't think there's a definite answer, just too many variables in hunting to nail it down other than a ball park figure, even then things can happen that none of us can explain.
Again, I can only go off my own experience but the problem I've seen most times with cast is when a guy messes up & loses an animal he goes home & makes his ammo hotter. To me, this is going the wrong way, a big heavy cast bullet, no matter how tough can only stand so much strain & then it's going to fail but if you let it work in the 1000-1300 fps range where most alloys are in their comfort zone you will have a successful out come, my experience.
Before chronographs, I always started out by shooting a mild, book load & increasing until it started to get nice & tight, then when it started to open back up I stopped & called it good.
Later on when I got my first chronograph I found out that most of those loads with heavy bullets were almost always in the 1100-1200 fps range.
Two things were happening here, one was, that seemed to be the "sweet" spot for many of the heavy cast bullets & it also seemed to be my "recoil" sweet spot. I could & did shoot many loads much hotter in the early years but my 1100-1200 fps loads were zipping through deer, elk, bears, antelope, lions, moose, hogs. Why punish myself with more recoil in a short range, iron sighted gun that was killing everything with ease by going up the scale, made no sense!
I've probably taken somewhere around 20 head of game with jacketed handgun bullets, not many, but back in the day there weren't many good six gun bullets to pick from & cast were so much easier to make & shoot by the thousands.
Since recoil goes up about 3-1 compared to velocity why punish yourself & your gun to make a 50 yd or under shot on a 200 lb deer? These are just my thoughts, agree or disagree. Like I said earlier, that's why they make chocolate & vanilla.
I always think it's best to go up in caliber & bullet rather than stress a smaller one. Heavy bullets, reasonable velocity & great accuracy will get you there, again just my thoughts.

Dick