@PNdad,
Public sharing is going to go to most people. Adding a second share on someone's page is not necessarily going to mean they are more likely to see it, plus it's more work for you. It's unlikely it'll give you a lot of promotion for the time you'll spend doing such things.
Understand that the % of people who see any given post isn't always due to privacy settings; it's also due to the sheer volume of stuff we all wade through, every single day. Note: most pages and groups and profiles, even popular ones, only get about a 5 - 10% distribution/share/review of their content because we are all seeing a tsunami of data every day.