FYI - Accuracy with a .32M will get it done
Regarding all the doubts about .32 Mag. It's got the penetration and some mass and diameter to work with. If you combine that with marksmenship, your in good shape.
I do my target practice starting just before dusk so I get in some daylight practice. Then I continue until 30 minutes after dark.
In this way, I get practice in daylight, at dusk, and after dark. I get my most practice after dark.
I started doing this because I live in WA State and it gets dark soon after I get off work in later winter and early spring. In mid-winter it gets dark at 4:30 PM. So I started practicing this way because I couldn't get to the shooting range any sooner.
However, I developed the ability to shoot well in daylight, dusk (twilight) and in the dark by moonlight or even starlight. I don't have a laser or any other gadgets.
I use the sights during daylight at 15 yards. At twilight I used sights until it's tough to see them, then I point shoot. All twilight shooting done at 10 yards. After dark I do all point shooting at 7 yards.
My cousin is an excellent shot with his .44 Magnum in daylight, but he never in his life target practiced after dark.
He and I normally practice solitary, but on a few occasion we shot together.
He can outshoot me in daylight, but that's how he does all his practice. He's really good and put's multiple shots through the same hole at 15 yards.
However, at twilight we are equally decent shots.
After dark I'm still hitting the target point shooting at 7 yards and I'm all in the second ring out or closer. Some bulls eyes too. He's missing the target entirely, but then he never practiced after dark before.
The point is this: Practice under the conditions you might need to shoot for self defense. When I first started practicing in the dark, I couldn't even find the safety to put it off. After practice, I can now draw, knock safety off, and then speed shoot my .32 ACP Firestorm with all center mass hits in second ring and first ring. Same with my .32Mag Ruger SP101.
In the dark, I'm hitting center mass consistently with my .32s and my cousin is missing consistently with his .44 Mag. Sometimes he completely misses the man sized target. He can't do any better with my .32s either. He has no experience in the dark and no experience point shooting. He says the muzzle flash blinds him and he can't see the target at all. That's because he's trying to use the sights by moonlight (big mistake).
My eyes are no better than his, but I don't have any muzzle flash problems after dark. Why? Because I'm only looking at the target, not the gun or sights. It's like when an oncoming car has bright lights aimed at you when you're driving. If you look at the oncoming lights you'll go blind. If you avert your eyes from the oncoming car lights, you can still see the road. Same thing here. I do it without even thinking because I've been practicing this way for some time.
The bottom line is this: A .32 Mag will get it done if you can hit your target center mass consistently in all conditions. I also do this in the rain and cold.
My cousin is an expert marksmen under ideal daylight, warm, dry conditions as he practices in. I'm a decent shot under all conditions.
My .32 Mag or even my .32 ACP are more deadly in my hands at night than his .44 Mag in his.
Accuracy counts more than caliber. So yes, the .32 Mag can get it done.