Loads with defensive capability are not rare, the trick is to find the best one for a given use environment.
Up to about 7 yards, darn near anything will work. The load hits like a semi solid mass, think of a giant Glaser Safety Slug. After that, small pellets lose their energy and scatter faster than large ones. The downside of large ones is the possibility of overpenetration, Given a typical use environment of an apartment building or SFD with a wooden frame and lath and plaster walls or drywall, the possibility exists of pellets exiting the target and harming someone else on the other side of a wall.
For HD, I recommend measuring the longest possible shot opportunity, adding one yard for GPs, and patterning divers loads. What you want is a pattern hand sized or smaller, this keeps the energy concentrated in a small area.
After that, use the one that meets the criteria with the smallest pellets to reduce the chances of overpenetration. I would keep some buck around in case things get bad outside and we have to militia things up also.
This has been covered before, mine the Archive for gigs of input.
HTH...
