The Remington 125 grain semi jacked hollow point was the handgun load with the highest percentage of one shot stops as of the mid 1990's. Not sure now, but I am sure it's still right up there. Contrary to popular belief, 110 and 125 grain hp's will not penetrate 1 inch, then stop. They offer reliable penetration for most all civillian self defense uses. Remember, humans are more effected by shock then most wild animals, also remember stoping power is most often acheived by drastic loss of blood pressure, causing the brain to shut down, This is best acheived by massive trauma to the heart and lungs, causing rapid loss of blood pressure. This is best acheived by a rapidly expanding hollow point that reaches the heart / lungs as it expands, causing maximum damage. Now if your shooting thru car doors, or at folks wearing numerous layers of thick, heavy leather / canvas winter clothing, then I could see a 158 grain XTP. Look at the construction, size, thickness, and shape of the average human torso - you don't need or want a bullet that will "shoot thru both shoulders of an elk" Whichever load you choose, practice a lot, then practice some more. Nothing wrong with practicing with less expensive / milder 38 spl loads, just remember to mix in enough full power loads so they are not a suprise to you when fired. Shoot double action only, just like you would in a real situation. You would be amazed how fast and accurate you can be with a little practice.
Larry