Outlook express / Thunderbird , VPN and outgoing mail server combination?

If I use VPN like anchorfree hotspot shield or packetix… in conjunction with outlook express or thunderbird. Are there any special settings I need to apply to Outlook or Thunderbird?

What is in your oppinion the best email management programe and best free vpn, best combination?

Do I need to set my outgoing mail server to the server of the country that vpn’s ip is from or the country where our computers and servers are.

Thank you.