I think you're missing the point all together.
Most gun fights are over in 3 shots. But all situations are different, you may have to reload.
If you fire a full house 357mag inside your home you WILL experience hearing loss.
I have a 357 for home defense loaded with 38spl+P. I have speed loaders scattered through out the house filled with full house 125gr 357mag loads. If I do have to reload I figure I'm going to use my 357 to it's full potential - that's what I have it for - hearing loss be (darned!) Better deaf than dead - IMHO
As to your original question, my answer is - Shot Placement. Shot placement is more important than penetration. As to 125gr vs. 158gr? What's better, hitting the perp in the chest with a 22 or missing him with a bazooka?
Every shot is different. Will the projectile penetrate the sternum before it enters the chest cavity? Or maybe a rib first? Or maybe slide between the ribs? What if it's a head shot? What if the perp twists and that bullet goes through his arm first?
What if...what if...what if...
Many people suffer from "Analyzation Paralyzation"
Like my father says, "Don't pick knits."
Pick a load, select an action to defend your home and family and PRACTICE it.