Noreaster - thanks for putting it bluntly . . I don't know any other way to say it. You have to look at life the way it really is . . . . although it is good to go through "scenarios" . . no one, and I mean NO ONE knows how they will react in a life or death situation . . . even the seasoned veteran. I was shot at many years ago while taking a call at night (I worked ambulance) and on several occasions, arrived at scenes where firearms were involved (i.e. shots had been fired with individuals down and no one knowing what was taking place or going on) and I've also been in situations with individuals high on dope who were doing their best to "take me out". When a situation like that arises, the adrenline kicks in and all you can hope for is that your training kicks in as well.
I CCW a .357 but I rarely have 357s in it - usually 38 spls. I practice with 38spls and 357 both though. Most SD situations are going to be "close up" and will basically happen so fast that you'll barely have time to react. At the range, I see very little difference in either of those cartridges at the range (distance) I am practicing at. You make a very good point. We all practice at SD targets (most of us anyway) "straight on". Real life does not always mimic that. A person should practice shooting at different angles as well. Personally, I'm not so concerned about how my weapon functions at say 25 or 50 yards, utilizing both 357 and 38 spls. and the differences of where those ammos hit at that range. I'm more concerned that regardless of which ammo I have in my weapon, that I can hit central mass at 5 to 10 feet for self defense purposes. At those ranges, with all the factors figured in of surprise, fear, adrenlin, reaction time, etc., I don't really see worry of practicing with the cheaper 38 spl and carrying 357.