Because the KSG does have two magazine tubes and does not automatically switch to the other tube when the first is empty, or alternately feed from each tube, many people have the idea of loading buck in one, slugs in the other and switching back and forth on the run.
That's confusing and as said, you wind up dumping a good round out of the chamber or "forgetting" which tube is which and firing the wrong shell.
A serious "my bad" would be getting faced with a target at 75 yards and mistakenly firing a buckshot load.
That could be a fatal mistake.
A possible better option is to just "Dutch load" the magazines like some people load standard single tube guns by alternating slugs and buckshot.
One expert explained this as a possible mag load for a car stop situation.
The first shell or two would be slugs to penetrate the car, the following shells would be buckshot for when they bail out, possibly finishing with a slug or two as they move away trying to escape and put some distance between you and them.
My idea of working with any gun is to keep it as simple as possible so you won't mess up under stress.
In a home defense situation a full load of buckshot is as simple and as effective as it gets.
For those turned off by the high prices of the bullpup shotguns, there's the Bullpup Armory shotgun conversion that converts a standard Remington 870 or Mossberg 500 series pump gun to a bullpup.
This is great if you already have a gun and it's an easy conversion that can be de-converted easily back to the stock configuration.
The only down side is that in order to remove the barrel or do a good clean job you have to more or less disassemble everything off the gun.
http://www.bullpuparmory.com/Default.asp