DirSync Servers Guidance?

Greetings!

Looking for some guidance in what to set our DirSync servers in Active Roles Server 7.3. Our company has 3 servers located in one location, with web sites each on those same servers, but the bulk of our users live across the country. We are experiencing extreme lag on the web interface from those users since our DirSync servers are currently pointing to DCs where the ARS servers are located. Is this wrong? Does anybody have tips to speed up the web interface for our users across the country?

Thank you!