Insofar as practice is concerned, I am a competitive (less so as I age) NRA High Power target shooter. I find that the "muscle memory" skills necessary for offhand or rapid fire target shooting with a center fire match rifle directly transfer to more powerful bolt actions used for hunting in Africa.
Thus I can practice less with the .375 or .458. In fact I think practicing excessively with a .458 will actually hurt, because developing a flinch is more likely. The .375 has WAAAAY less recoil and that is why I prefer it.
Once I get a zero and a reasonable group, I don't shoot off the bench. Just sticks and offhand. I find that, to get a good natural point of aim, I need to face more toward the target with sticks than offhand. I don't care about little bitty groups, just reasonable ones. Also I don't care about getting the ;last fps of velocity. 2500 fps with a .375 is plenty for anything.
