Q1: You should be on East unless support had a good reason to change you. First, I would do a couple of pings to the East and Central nodes to see which one has the least latency. If East looks better, open a ticket and have them move you back.
Q2: See this link for the hostnames: http://forums.voipo.com/showthread.php?t=1677
Unless you are a grandfathered BYOD and have obtained your SIP credentials, you can't use East or Central servers for your softphone. You will have to use the BYOD server by enabling that option in vPanel and using the SIP credentials generated there.
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