If I were equipping with a SxS, I'd want ejectors instead of extractors for faster reloading, a big bead for fast pickup and two triggers.
I'd also establish which barrel worked best with slugs and do some fast COFs with a Buck And Ball loading, say slug in one barrel and 00 in t'other.
Read the old thread on a Lupara for some ideas.....
My double is a hammer gun, it sits ready with no springs being stressed. Two barrels of #1 Buck. If it is a close fight, it will be dropped on the floor, or used as a baseball bat. Immediate transition to pistol, if I am still in the fight and still needing to fight.
If I do have time and the need, my Bugout Bag has 10 rounds of #00 buck. That Bug out bag also has 3 30 round mags for my XCR, and 3 additional mags for one of my two warriors with a X200B light attached.
So depending on how I assess the threat, I grab the Bugout bag I have extra ammo for which ever long arm I grab, an additional pistol assuming I had time to grab my carry Colt Gunsite Pistol Government. Extra batteries, extra flashlights, Small aid kit. Extra phone battery and binoculars. And a sheath knife, usually my ole K-Bar from Vietnam, and yes it has been blooded.
That is how I approach the shot gun question. The shot gun is #1 choice, but the XCR is there set up for HD duty, with Aimpoint on 100% 24/7 and a SureFire 9P & LED head,with quick detach Larue mounts. In the Bug out bag above, is also the Aimpoint 3X magnifier, in a Larue Quick detach flip mount too. The Idea is, given the time, to be able to configure quickly if the carbine is chosen over the shotgun. The Carbine is set up at home normally with the Aimpoint and Light only.
Just my way. Allows me to go to war in my house even if I am buck naked (this is not a pretty picture by the way, think whale out of water) with long arm of choice and the Bugout bag slung over my shoulder. Besides, if I am lucky the VCA will just go down laughing.
I normally have my Colt holstered at home when up and dressed.
Go figure.
Fred