Random thoughts from the FWIW Dept:
Plain-Jane, 12 GA, 2-3/4", 9-pellet 00 Buck is some bad stuff that works great against unarmored targets. We used it for years in the deer woods of Alabama. There's also a 2-3/4", 12-pelet load available for those who might care to seek it out. We used to call them "short magnums". The down side is that they cost more and kick a lot more.....plus, my early testing indicated that they don't pattern as well at distance, leastways, that was case with Remington's version.
Continuing down the payload VS recoil path...I've shot a few of the true 3"-magnum, 15-pellet 00 Buck loads, enough to say for sure that it takes a tougher guy than me to use them things...meaning that to me, they're even more obnoxious to shoot than a common slug-load.
On the opposite end of the scale, there's some "reduced recoil" buck shot loads on the market these days which are in fact, much easier on the shooter than a "regular" load. I've tested the Remington "00" version and the Federal 00 "Law Enforcement" version, and found that they both work just as advertised. Of course, the laws of physics dictates that softer recoil comes at a price. In this case, the price is paid by reducing the powder charge and topping it off with only 8 pellets instead of 9. On the surface, that don't seem like much to give up, and in fact, I'm perty-sure that the folks who are concerned about "too much penetration" would consider it a bonus. In my case though, my initial testing showed it to be unacceptable... meaning that neither brand had enough power to reliably work the action of my Remington 1100, 18-1/2" riot gun, so I traded-off what I had left rather than test it any further.
Still though, it might be something for the pump-gun guys to consider.
And just in passing, perceived recoil relative to any given load has a lot to do with both the weight of one's gun, and how much drop the butt stock has (or don't have). In other words, lighter guns are easier to handle, but heavier guns tend to have less "kick".
Just some stuff to consider before plunkin' down your money.
Hope it helped someone.
DGW