Tandems have a 30 to 40% greater aero load than the same captain on his road bike. So tandem aerodynamics are dominated by the captain (assuming the captain is bigger). In crosswind situations, tandems have a higher aero drag than two single bike who can echelon in the wind. Since the captain and stoker are dynamically connected via the timing chain, they can work perfectly together or fight each other which will not be intentional or obvious to the team.

My advice is relax and go with the flow. Do not overthink it. If either team member feels the cadence is too high or low try to make adjustments and find a middle ground. Captains should try to make their stoker as comfortable and secure as possible. The more the stoker relaxes the better the energy transfer, team work and fun.

Since captains see what is ahead, they typically put in the first increment of power. So as the ride progresses, if the captain always supplies the needed energy to maintain speed, it is a tougher day in the saddle. The only command I typically use is more power. She then increases power so that we better share added energy requirements.

That is not an important part of riding but if your stoker wants to contribute and share the power making, he/she has to be informed to get in the game early enough so that the captain does not have to take all the accelerations. YMMV.