[Tex/LaTex] How to set font size of beamer items

beamerfontsitemize

I am putting together a beamer theme for internal use (which has, I am afraid) to look rather like Powerpoint. One thing I can't work out how to do is to set the font size of the text that appears after the bullet in an item or a subitem. As I understand the reference manual, I need to use \setbeamerfont{some beamer element}.

I wondered if it was itemize body but that seems not to be the case. An example of something that does not work:

\documentclass[aspectration=43]{beamer}
\usepackage{geometry}
\usepackage{fontspec}
\geometry{paperwidth=25.4cm, paperheight=19.05cm}

\setbeamerfont{itemize body}{family=\sffamily, size={\fontsize{18}{18}}}

\begin{document}
\begin{frame}
  \begin{itemize}
  \item First item
  \item Second item
    \begin{itemize}
    \item Subitem
    \end{itemize}
  \end{itemize}
\end{frame}
\end{document}

I have looked at the list of elements and cannot work out which should apply.

Best Answer

An Overview of the available options can be found at http://www.cpt.univ-mrs.fr/~masson/latex/Beamer-appearance-cheat-sheet.pdf

\documentclass[aspectration=43]{beamer}
%\usepackage{geometry}
\geometry{paperwidth=25.4cm, paperheight=19.05cm}

\setbeamerfont{itemize/enumerate body}{family=\sffamily, size={\fontsize{18}{18}}}
\setbeamerfont{itemize/enumerate subbody}{family=\sffamily, size={\fontsize{18}{18}}}

\begin{document}
\begin{frame}
  \begin{itemize}
  \item First item
  \item Second item
    \begin{itemize}
    \item Subitem
    \end{itemize}
  \end{itemize}
\end{frame}
\end{document}