1) The association of a station on the master controller to a station on the remote controller is arbitrary. For example, you can associate station 1 on the master controller with any station on the remote controller. They do not have to have the same index. Note that when specifying a remote station, you need to give the IP of the remote controller, and station index.
2) To configure a second master station, go to Edit Options -> Configure Master -> and set a station for ‘Master 2’. Then Submit. Back to the homepage, click on the gears icon next to a station, and you should see both ‘Use Master 1’ and ‘Use Master 2’ flags.