What is the right approach to vapour retarder/barrier for my assembly in Atlantic Canada (zone 6)?

None, 6-mil poly, smart (variable permeability) membrane, painted gypsum board, combination, something else? Does a smart retarder perform better/worse with/without a service cavity (separation from vs contact with wallboard)? Specific… None, 6-mil poly, smart (variable permeability) membrane, painted gypsum board, combination, something else? Does a smart retarder perform better/worse with/without a service cavity (separation from vs contact with wallboard)? Specific…Read MoreGreenBuildingAdvisor