You can use Zero without pins to lower it's weight - Raspberry have resellers in some countries, so base model (without pin connectors) cost only 5$.
Also try putting some custom cables to reduce lift disturbance on usb connector side (it might be causing a lot of instabilities during the flight).
Additionally, if you need more stable video, try to remove protectors - they reduce performance a lot, especially with windy weather.
I'm finishing my own setup with some extra features, will keep you guys posted.