Of course, it's not difficult at all. It is exactly, what I did. I have copied both [readers] out of My Subscription, completely.
Oscam is connected to both servers for 5 minutes, then Backup server is disconnected because of inactivity.
So there is a discrepancy between your recommendation concerning main/backup servers and your oscam.server settings on Subscription page.
See an attachment. If the oscam has to be connected to both servers all the time, then the inactivity setting has to be removed at least from the backup [reader].