I put a gimbal on DJI phantom. The overall weight is good. No need to adjust any parameter. It fly great. And I decided to change stock receiver with Futaba 6203SB and T8FG. So, tilt control is easier. You can easily do 90 degree tilt :-)
When power up the phantom. Your GoPro camera will automatically turn on. And it’ll always charge your GoPro battery. As you saw in video. I turned off GoPro and charging light turn on.
Unlike other gimbal that I have. You’ll have space about 1cm below camera.
I tested by not put camera and turn on gimbal. Motor shake a lot. So don’t try it. :-)
Swiss grade aluminium. And motor from Maxon. Really tiny but high performance.
Roll motor on back side. 
CG of the gimbal is perfect with camera. On document it said do not put any filter to cover lens. But i tested by put Layer Lens. CG is bad but it work fine.
Pair with Futaba T8FG. So, I feel more comfortable on it.
This is how i put PMU and GCU inside my phantom. I borrow photo from rcgroup. His photo really good and clear :-)
Sarawuth: I’m still looking for a simple solution to avoid charging of the GoPro in order to keep the main battery for flying. The GoPro accu don’t need to be charged during flight, that holds long enough when you start fully loaded. A simple switch in the loading pin of the gimble or so would be fine. Then its variable if you charge or not.