Hello Jake12. Thank you for the inquiry. As of the moment the IPad pros is not yet recommended for your DJI Phantom 4 Advanced. For reference I will be posting the list of recommended mobile device for your DJI Phantom 4 Advanced. Thank you for your support.
Devices over 6.75 inches wide (including the case) will not fit into the remote controller mount. If you have a mobile device larger than that, you'll need to use a mount (like one of these).