Fairly new here to tandeming also, but other than during first days of starts and stops, I'm feeling pretty confident. But we also have been touring for years on a motorcycle, and I think that has helped us both. But it is definitely different than single bikes, starts and stops require a bit more thought and control (no more waiting for the absolute last millisecond to unclip trying to time a stoplight). I guess you could say just be more deliberate...

You've probably already read these, but they certainly helped me (albeit they make it clear that the captain is has 99% of the responsibility).
Advice for New Riders of Tandems
The Proper Method
Tandem Bicycles
First Ride - Tandem Cycle Works

Probably the best is just experience; just put some miles on. We love it, and have ridden 30 to 50 miles on it almost every weekend for the last few months that we've had it.

p.s. For me at least, and this may be in your captain's mind, I would be extremely upset if I failed and got my wife hurt. We've talked about the risks, especially related to the motorcycle riding, and have both agreed we understand and accept it, but I still think about it...