Parameters are accessed with C4DAtom::GetParameter()/ C4DAtom::SetParameter(). See page_maxonapi_getting_started_foundations_cinema_parameters.
Parameter: Custom Number of Render Threads
PREF_RENDERER_THREADCUSTOMParameter: Adapt Thread Priority
PREF_RENDERER_THREADPRIORITYParameter: Lower Process Priority
PREF_RENDERER_LOWERPROCESSPRIORITYParameter: Renderer Log File
PREF_RENDERER_CREATELOGParameter: Global Illumination Info in Console
PREF_RENDERER_GLOBALILLUMParameter: Render Queue Log
PREF_RENDERER_RENDERQUEUELOGParameter: Auto Renaming
PREF_RENDERER_RENDERQUEUE_AUTORENAME