125 is all youd need, lol all i think ive ever use has been 125 hp and sp so im not so sure on which is better but as far as going out to over 20 yards the 125 hasnt failed me yet although i used some s&b 158 sp when i bought my newest toy, and other than the reviews and bad cycling of my pistol due to power residue it seemed fine but i also was not trying to record muzzle velocity or anything due to my lack of equipment and excitment of my new piece. but overall i wouldnt think anything about them stacking up against one another unless your planning on doing some long range pistol shooting in a competition setting where all that will definately play a big factor. but for personal defense id suggest the 125 as it will undoubtably be faster for the close range that will be expected in this scenerio. plus if your using hollow points the 125 would spread better and use full potential of the hp factor but these are my views on it. hope it helps your decision.

I've read some recommendations for heavier bullet weights during cold winter months, when more layers of clothing might be involved. Supposedly heavier bullets penetrate better, although, I've never done any ballistic gellatin testing myself. I do know that heavy bullets will put a whitetail deer down with authority inside 100 yards.

True but at same time at the close range that said event would happen in the 33 extra grains are not going to give much different results because they will be connecting at almost terminal velocity of the particular round at the average shootout distance of 7yards so its really up to your preference and what you believe is best or feel safer with but I'm gonna let you know that small amount of extra weight isn't gonna make much difference other than the fact that whoever might be behind the perpetual needs to be able to duck quicker

Perp * darn spell check.. besides an average jacket is not going to cause a 357 mag to not do its inevitable job to tear s**t up as its like getting hit by a Volkswagen at mach2 in a spot no bigger than a pencil

A Heavy Leather Coat is the best example I can think of. I've read that this might cause the HP to expand prior to entry, and slow down the projectile, reducing the energy transfer to the target. The author suggested that heavier bullets would help offset this.

I've also read somewhere that .38 Specials and .357 Magnums are often Factory Sighted with 158 Grain Bullets in mind. I'm not sure if that's true or not?

not so sure what most of them are sighted in with youd have to look up the particular pistols specifications to find that out besides if the jacket causes early expansion theyll just look forward to a larger intry wound

I prefer the 158 grain.