Correct, you need to hide address on G+ L. You need to list your actual address in the dashboard though.
Here are the service area settings to be sure your address gets hidden on your listing.
SELECT: I deliver goods and services to my customers at their location
BE SURE THIS IS DESELECTED: I also serve customers at my business address
That will signal Google to hide your address.
As far as your site and citations - it really helps to show your address there because Google matches to the address in dash even though it's not showing live.
However, so you know for clients, some people are worried about privacy or security and don't want their address showing anywhere. So there are citation sites that allow you to enter a listing without an address. And on their site you could do NAP with street address missing and city only. But it's best to do full NAP on site and citations if possible.
New advertising option:
A review of your product or service posted by a Sterling Sky employee. This will also be shared on the Sterling Sky & LSF Twitter accounts, our Facebook group, LinkedIn, and both newsletters.