Who said the 38 was on the low end of stopping power, some statistics expert? A plain jane 38 Spl with a 158 gn semi-wadcutter in a standard pressure loading has been known to shoot through assailants in close quarters confrontations. Get a S&W 5 shot j-frame, my preference is the M38 with the concealed hammer, a couple of hundred rounds of wadcutter target/practice loads and a couple of boxes of 158 gn swc ammo and you should be set to go.
Check back on your 'statistics' to see when they started being recorded - bet you will find it wasn't all that long ago, probably after the 357 became vogue for police departments, and I doubt police departments began refining the data until later.....
You really do not need a 357 snubbie for personal defense - you do not get full magnum velocities but you sure get the bark and flash (which never stopped anything).
About 13 oz is the lightest you would want - below that you may have difficulty with bullets 'walking' out of the case due to recoil and the light weight of the revolver - like when S&W first came out with the Titanium snubbies at 12 oz they were afraid the bullets, esp with reloads, would 'walk' and jam the gun - I never saw that happen though. And most S&W snubbies come with a 1&7/8" bbl.
If you want at least 9mm stopping power then step up to the 38 Spl; loadings from 158 gn to 200 gn outweigh the 9mm. And it doesn't matter what you shoot, you gotta hit them in order to get them to stop, or seriously reconsider their chosen profession..............jmtcw.