Thanks very much, GunEnvy, for your detailed reply. Let me state what I think I heard so you can tell me if I got it right (or wrong!) Is there a source that you know to research shootings other than the anecdotes in gun and leo magazines?
1) within a caliber, lighter is faster, faster is generally better, but 'too' light may be deflected by denser tissue and may be less effective at stopping.
2) across calibers, heavier is less susceptible to 'dense tissue deflection.'
This leads me here: given my selection of cartridge size (9mm, chosen for low ammo cost and ease of cc), and given the short length of one of my barrels, 115 grain would seem to make the best use of that short barrel. The caveat being that the lighter bullet weight may be more subject to dense tissue deflection.
So, my logic leads me to a lighter bullet, eyes open to the deflection possibility. Since center of mass is where I'm aiming for SD, deflection shouldn't prevail as an overriding concern anyway, since center of mass is all about soft tissue? Or, do ribs and sternum trump velocity?
Or....am I over-thinking this?