The Offset of the card itself is not that interesting… its more the connected TV Screens. All Screens have different times they need to display a frame.
Try catch ‘n’ syc for iPhones to get measured results better than eyeballing it.
Also… try to avoid H264. The use of i-frames makes syncing difficult. Every time playback starts the frames can be slightly off and different in sync.
Check this support page for nuendo out:
Scroll down to recommended codecs and use one of those.
hope this helps.
Hendrix