I would think that if you came home to find your home occupied, shooting first would be your best bet if reclaiming your property was the highest goal. Once you get the authorities involved, you lose any self-defense claim. You can't say you feel threatened in your home if you've called the police and they've opened up a file.
If you shoot and then call the police, you can say you returned home to find invaders, felt threatened in your home, and shot them in self defense. If there are women and children remaining, it's your word against theirs, and their last act before you shot their menfolk was to be in your home when you arrived to an ambush.
It would be an interesting national spectacle, with Left/Right lining up to choose sides, just like in the Zimmerman case. Hell, why not, at this point. I hope it happens.