Commander is ultimately responsible for safe conduct of the flight regardless whether he/she is PF or PNF thus the commander must be ready to take over any time if he/she deems necessary. Having said that PNF MUST be ready to take over in case of incapacitation, consequently F/O must be on controls, if PNF, specially during critical stages of the flight without obstructing the PF. I've had similar situations where a simple exchange of words resolved the issue. On the other hand hard rudder might be mistaken for interference. Why not speak up? The OM A states unambiguously both pilots are on controls below 1500 ft. Insurance companies love this sentence, remember famous BA 777 where FO landed the aircraft.
