One major tip i have to ensure the delay between your machine and the lab in the US isn't too bad is to use the links at the top of the screen rather than the ones on the desktop of the RDP machines. They will all be at the top middle of the screen and i have heard from several people these allow faster access and less delay.
I personally didn't use this method as I didn't know about it and still passed it so the delay is a challenge but if you know your stuff I think it wont matter.
Good luck!!