Q: If I have two Z-20s listed in My Profile, can I assign both of them to 1Number?

No. 1Number can accept only one of each type of videophone. For example, if you have two Z-20s, two Z5 numbers and either a Sorenson or Purple videophone number; listed in your My Profile, you can only assign one Z-20, one Z5 and either the Sorenson or Purple number.