Your twinview problem is very easy to solve. You are using:
Option "MetaModes" "1200x1024,null; 1024x768,null; 800x600,800x600; 640x480,640x480"
(likely 1200x1024 needs to be 1280x1024 but the topic isn't about that)
The syntax of metamodes is as following:
"resolution screen1, resolution screen2"
where in your case screen1 is your DFP and screen2 is your TV. At the moment X starts up at 1200x1024 on screen 1. When X is in that mode, screen2 will be blank because its value is "null". When you would switch to 800x600 on your DFP your TV would become active, because then its resolution isn't null.
And in your case the same image would appear on both screens because of "clone".
I would read a bit more about twinview in the docs and good luck.