How do I make an emualator for a certain device?

How do I make an emualator for a certain device?

So I'm trying to make a new emulator in "Virtual Devcice Manager" in
Eclipse. I want it to be the same as a certain device (same screen size,
same android version installed as it is by default on that device etc.).
The device I'm trying to "re-create" as an emulator is Sony Xperia Z. I
searched for the phone's specs and this is what I found:
Android 4.1
12.7cm (5") screen
I then tried to create a new virtual device in eclipse and I don't have
any of these options. The closest Android version that Eclipse lets you
use for Virtual device is 4.1.2 and the closest screen size is 5.1" WVGA
If I created a virtual device like this, would it be good? Would an
application that I ran on this virtual device behave the exact same way as
on actual Sony Xperia Z?