A few points.
Two things are neccessary for stopping an attack when the aggressor does not want to stop: rapid exsanguination and shutting down the CNS. In order to do either one, you need something that is going to penetrate deep enough one time to get through heavy bone and intervening anatomy. The major vessels and the CNS are well protected. The FBI minimum standard for penetration is 12" in calibrated ballistic gel. That standard has been supported through research of actual shootings and post mortem examinations. It is a minimum standard.
No birdshot reaches that penetration depth. Some buckshot doesn't.
Plan accordingly.
Glasers don't work. Look at some of the testing by people that get paid to study terminal ballistics, that are peer reviewed, and accepted as SMEs. They don't recommend Glasers.
Birdshot, or more accurately BS, is not a reliable fight stopper. Should, may, might, and ought to are not criteria that I think hold merit when I'm defending my life or someone else's. I've seen several BS shootings in which the attack continued after the first shot, and one that continued after several. I know of two OIS in which officers were shot in the head/face and continued to fight, including one that chased the turd for several blocks.
LL are typically a bad idea. You open yourself up to all kinds of liability if you have not been properly trained in its use. LL is backed up with lethal rounds when it is deployed, and that's with reason.
Magnum turkey loads generate a lot of recoil. Not a good thing when you may need to make quick follow up shots. Another consideration is muzzle blast.
Using the argument that because somebody wouldn't want to get shot/stabbed/hit with something is flawed. I don't want to get stabbed with a pencil but that does not mean that a pencil is a good defensive weapon. If it is all you have fine, but if there are other options then it loses merit.
There are better options in .38 than Nyclads. Lots better.
If your plan for using BS includes hitting the same spot already hit so that your projos go deeper, that is idealistic and not something I would even consider. Not on a two way range with a potentially moving target in the dark that gets to shoot back and has a say in how things go. I don't see this as a reliable circumstance.
Tightened chokes with BS just means that you will have more shallow penetrations in a tighter area. If the area impacted still has the major vessels and CNS structures under a lot of protective anatomy you aren't any better off.
Bubba, you're exactly right. The plating not only reduces deformation in the bore it also increases penetration. That's a known factor.
Anything that is going to reliably stop an aggressor will penetrate drywall.
The trade off is going to be what you as an individual are comfortable with. Be aware of your target and what is behind it. Position yourself where you minimize downrange hazards if possible. At work or at home, I'm not going with less than 00. The new 1B load from Federal will go a long, long way towards reducing downrange hazards once it becomes more widely available due to the smaller shot size.