Treb, I know I'm probably not "qualified" to say this (I'm a shotgun newb, remember), but: You seem a bit over-worried about learning about the Shotgun. Personally, I don't think it's that hard, really. True, there're different techniques, I'm sure! But if you keep it simple, it'll still be extremely effective when you need it.
With buckshot, at least 000 (like I'm going to try out) buckshot, you'll have 9-10
9mm / .36" projectiles hitting the target AT ONCE; and that's like getting hit with about 10 shots from an automatic 9mm machine-gun all
at once. Pump shotgun quick to load another, and *BOOM* again, that's 18-20 9mm projectiles within 2-3 seconds. We're talking serious "stopping power" that I wouldn't think even a semi-auto .223 or .30 carbine could match!
Again, if worried about buckshot not being TOO effective, then load a slug next in line, or 2 shells down, or wherever you're comfortable.
I ordered copperplate buckshot, and it stated it's also better for deeper penetration, since the plate helps the buckshot projectiles from deforming on impact. I picked it since if I went hunting with 'em, I'd not have lead inside the game I killed. lol! But it works both ways here, I guess: penetration and no health hazards.
It's good you plan on taking a class; I am going to soon, as well. Just don't be so worried about the complication of shotguns. It's not going to be that hard.
If anyone tries to complicate it, you just say "KISS!" They say "What?" You say "
Keep
It
Simple,
Stupid!"
P.S. I'm sure you can find maybe some soft lead Hollow Point slugs online somewhere. Those'd probably have more chance of not "overpenetrating" than the hardcast stuffl. Me, I need all the penetration I can get, since I'm using the shotgun to take down a bear if I have to.