latex memoir 8pt

How to get 8 pt in memoir? In contrast to the default classes, memoir has 12 different sizes for normalsize. Five of them allow you to get a size of 8pt in your document. 9pt 10pt 11pt 12pt 14p

\documenclass[9pt]{memoir}
\begin{document}
\small
the text now is in 8pt
\end{document}

\documenclass[10pt]{memoir}
\begin{document}
\footnotesize
the text now is in 8pt too
\end{document}

\documenclass[11pt]{memoir}
\begin{document}
\scriptsize
the text now is in 8pt too
\end{document}

\documenclass[12pt]{memoir}
\begin{document}
\tiny
the text is now also in 8pt
\end{document}

\documenclass[14pt]{memoir}
\begin{document}
\miniscule
the text is finally 8pt
\end{document}