I just preordered gopro 4 , im willing to mount it on my phantom vision ,now i found i can do a small weight add modyfication to work on zenmuse but i also wanted to utilize existing video fpv via app with linked gopro4 instead of phantom , what cables are video out etc to modyfy the existing system without messing arround with new fpv set and separate on screen data as well as moving the gimbal from the app

Try the Quickrelease from Dronexpert.nl

You can use your GOPRO_H3 or H4 on your Vision_plus platform, together with your Vison APP.

looking good , thank you