We would like to enable Lightning Sync to work with our outlook.  When we turn it on, we do not want to duplicate contacts that are in outlook and also in Salesforce.  Is there a way to identify that an outlook contact is already in Salesforce?  Also, we were thinking of turning on the Sync Both Ways initially to push outlook contacts that are not in Salesforce up to Salesforce.  What is the best way to insure all contacts are in SF and contacts we don't want to go to SF are not sent up?  Please advise.  Thanks.