Right or wrong the company (and FAA) policy is clear... no requirement to wear a mask when at the flight control once the door is closed. If you want the other pilot to wear a mask then simply ask them... if they refuse you can either operate the flight without a mask or pull yourself from the trip after contacting the CPO/FODM. The company guidance is clear that one pilot cannot coerce another to wear one regardless of what rationale they use. Until this changes nothing written within this thread matters. The simulator is a different issue... company policy is also clear that you will wear a mask at all time or be subject to disciplinary action to include termination... you cannot coerce the other pilots to not wear a mask.