We use extension mobility with over 500 end users. Build the phones like you normally would. Make sure to check mark Enable Extension Mobility Feature. And the log out profile should be

Make sure you have your subscribe/unsubscribe services for extension mobility login/logout and assign to device.

Then, build your mobility profiles for Jane Doe, extension, CSS and partion. What ever normally you would assign.

example: you have 10 people who come to the phone to login, do some work, logout. next person, logins, does some work, takes calls, logouts.

The phone is always returned to the basic device setting when you first built the phone.