Your best bet would be to go through the thread, join all of the American servers and stay in the ones who seem active after a day or two.
Also, Open port 7500 if you haven't already. Connecting through direct IP gives much better netplay.
EDIT: General message to everyone who joins.
Don't expect to get any action by joining the server, typing "wanna play" in the general chat, then leave after 10 seconds of not getting a reply. Some people do this. Not all, but some.
The thing is; sometimes people look away from their computers, but if you give it a little time, you will get a reply.
Another thing I'd like to suggest is changing your hamachi settings so you get a popup window of the chat whenever there's something new there. Don't worry, this won't disturb your other duties. If you have something else going on over it, it will simply blink orange down on the taskbar.