Well if he is found innocent or the charges are dismissed there will be a civil wrongful death trial 3 weeks later. During that trial self defense will not matter.
The only problem with a wrongful death trial is that Zimmerman has to have some tangible benefits that they can go after. He wasn't a wealthy man before all this started. Maybe try to attach his future income from movie or book deals? If he doesn't have anything you can't get anything.