Running a pack (in the case of Glasers) or a magazine or two of ammunition through a gun does not guarantee that it will "work" when needed. Since you only get one chance for X load to work, most people who are serious run somewhere around 200-250 rounds of a given load through a gun before they trust it. It also helps to practice with your carry load.
Anyway, the .45 in FMJ 230 grain format, delivers about 18" of penetration in gelatin. Not that gelatin necessarily shows what will happen in a human since skin, bones, and organs all have different consistencies and such. However, the original IWBA penetration standard was in fact 18" or more. The FBI standard was later 12" or more. People always seem to forget the "or more" part of things.
For a given bullet to be effective, it must reach the vital structures of a body. After that is a accomplished, then worry about maximizing tissue damage. (This is the "poke a hole theory" and doesn't account for the potential damage done by higher velocity projectiles, but this is the .45 ACP we're talking about and not a .357 Sig or a rifle, thus it is all about "poke a hole".)
If someone cannot afford - or these days given shortages even obtain - sufficient modern JHP to test/practice with, then FMJ is probably a better choice.
I'd certainly use FMJ over Glasers. While Glasers will penetrate heavy clothing, and sometimes even dry wall, they tend not to do so well in terms of penetrating flesh. Certainly getting penetration to vital organs is likely to be an issue.
