Beamer : Changing Font Size In Notes When Using \setbeameroption{show Notes On Second Screen}
Answer : You can define font size for notes with \setbeamerfont{note page}{size=\tiny} , default size is \small . Define the font size for notes as well as for subitems in notes with \setbeamerfont{note page}{size=\tiny} \addtobeamertemplate{note page}{\setbeamerfont{itemize/enumerate subbody}{size=\tiny}}{} as shown in this answer.