I would suggest contacting a GSD rescue in your area for help. They better have the ability to screen, match and place your dog...as well as have a good contract behind the dog should the new owner become unable to keep...at any time...during the lifetime of the dog.
I would start with this one..
German Shepherd Rescue of Los Angeles
I read through the policies and they do home visits, screen well and have a solid contract behind their dogs....which is all so important.