Luke, I don't know if this will help or not but in CTB O'Kane mentions that the control room helm was the Auxiliary Steering Station. That is also supported by this description from the USS Pampanito site:
Auxiliary Steering Station: The steering station is located amidships against the forward bulkhead. Under normal conditions, the steering wheel in the conning tower was used to control the rudder. This wheel was used in emergencies. In this area are:
- Steering wheel or helm
- Auxiliary gyrocompass
- Underwater log indicator
- Gyrocompass repeater
- Rudder angle indicator
- Dead reckoning analyzer indicator (lower forward)
- Motor order telegraph which transmitted speed orders to the Maneuvering Room where the motors were controlled
It looks like you are correct and that the helmsman would normally be in the CT, whether submerged or surfaced.
Dave - please correct me if needed.