I'd be interested to know how this works out if you get it going. I asked the same Q about syncing two tape machines a week or two ago. You'll have to stripe the tape with SMPTE time code. This means you'll lose a track. You could then feed this to a synchronizer.
What kind of ADAT are you getting? I'm not familiar with them myself so I wouldn't know what connections are available on them.
My initial idea was to sync my machines by just using the control ports on them but I've realised this would be impossible due to any tape slippage that might occur.
I'd say you'll be getting the ADAT to chase the Otari anyway as the Otari will be the "Master", generating the SMPTE from the striped track.
Which Otari 8 track do you have?
Vinny