A lot depends on the range you want to shoot Deer at. With a handgun, I limit myself to about 75yds on a good day. At 75 yds, from a 5&1/2 in 45 colt (Clone), about any 200 grn hard cast bullet at 900 fps or more will go completely through both shoulders. Anything more is just depending on how far you want the bullet to go after it's gone through the deer. A 200 grn bullet at 900 fps is doable with BP, and a multitude of modern smokeless powders.
If you have adjustable sights (Yuck!!!!!) on your revolver, you can set them for whatever load you pick. Mine has fixed sights and I try to load to the sights as they are set for my normal loads.
Use enough gun for the job, but no sense pounding your hands and arms for more when it's not needed. Many people find the heaver bullets to shoot more consistently to point of aim. One of my revolvers won't group the 200 grn as well as the 250 grns out past 50 yds. Something to think about, anyway.
Greeenriver