Exchange 2003 - Multiple SMTP Connectors

Hello! We currently have one SMTP Connector (this is Exchange 2003 Enterprise, SP2) that forwards everything (*) to an external SmartHost, Cost 1. The SmartHost is an external mail filtering company. This works fine now...internal email stays internal, and all outbound goes to the filtering service.

I am adding a second SMTP Connector as we have one customer that requires TLS encrypted emails.I know I have to create a second SMTP Connector, add the customer domain to it (i.e., companydomain.com), check the TLS box, and also forward it off the same email filtering company.

My question is around the cost...do I need to change the default cost of 1 on either connector? I read somewhere you should, but I read other articles that say Exchange automatically looks for the Connector that best suits and just uses that (so keep them both at 1).

So this is how it will look:
Connector 1: Forwards outbound to filtering company, *, Cost 1
Connector 2: Forwards outbound to filtering company, comanydomain.com, Cost 1

Any ideas are appreciated. Thanks!