Q: Palatino font size I'm using Palatino for my dissertation, but 10pt is too small and 11pt is too large (looks childish). I would like to select something in between. Any suggestions on how to do this? 
Edit: following the other threads, there seem to be three answers:


*

*(pdflatex, 11pt memoir, fix-cm, renew \normalsize): this only changes \normalsize (so not \small, \huge, etc.)
\documentclass[11pt,a4paper,twoside,openright]{memoir}
\renewcommand*{\rmdefault}{ppl}
\usepackage{fix-cm}
\renewcommand{\normalsize}{\fontsize{10.5pt}{12.5pt}\selectfont}
\begin{document}
{\tiny This is tiny}\\
{\scriptsize This is script size}\\
{\footnotesize This is footnote size}\\
{\small This is small}\\
{\normalsize This is normal size}\\
{\large This is large}\\
{\Large This is larger}\\
{\LARGE This is very large}\\
{\huge This is huge}\\
{\Huge This is very huge}
\end{document}


*(pdflatex, 11pt memoir, fix-cm, relscale): this doesn't work at all (since you would need to use \relscale{0.96} whenever changing from \normalsize to \small or something)
\documentclass[11pt,a4paper,twoside,openright]{memoir}
\renewcommand*{\rmdefault}{ppl}
\usepackage{fix-cm,relsize}
\begin{document}
\relscale{0.96}
{\tiny This is tiny}\\
{\scriptsize This is script size}\\
{\footnotesize This is footnote size}\\
{\small This is small}\\
{\normalsize This is normal size}\\
{\large This is large}\\
{\Large This is larger}\\
{\LARGE This is very large}\\
{\huge This is huge}\\
{\Huge This is very huge}
\end{document}


*(lualatex, 11pt memoir): this changes all type sizes (\normalsize, \small, \huge, etc.)
\documentclass[11pt,a4paper,twoside,openright]{memoir}
\usepackage{fontspec}
\setmainfont[Scale=0.96]{Palatino Linotype}
\begin{document}
{\tiny This is tiny}\\
{\scriptsize This is script size}\\
{\footnotesize This is footnote size}\\
{\small This is small}\\
{\normalsize This is normal size}\\
{\large This is large}\\
{\Large This is larger}\\
{\LARGE This is very large}\\
{\huge This is huge}\\
{\Huge This is very huge}
\end{document}

For example in my case, \normalsize was 10.91pt and afterwards 10.46pt. Perfect! Note also that in the third option, the system's Palatino font is used, while in the first two, URW Palladio is used. To conclude I would say that lualatex (or perhaps also xelatex etc.) is the way to go. The \usepackage[scale=0.95]{tgpagella} option mentioned in the comments also works, but this is specific to the font package.
However, there is still an issue remaining: how to change the math type size? I'm using \usepackage{lmodern}.

A: use also TeX Gyre Pagella Math:
\documentclass[11pt,a4paper,twoside,openright]{memoir}
\usepackage{unicode-math}
\setmainfont[Scale=0.96]{TeXGyre Pagella}
\setmathfont[Scale=0.96]{TeXGyrePagellaMath-Regular}
\begin{document}
{\tiny This is tiny}\\
{\scriptsize This is script size}\\
{\footnotesize This is footnote size}\\
{\small This is small}\\
{\normalsize This is normal size}\\
{\large This is large}\\
{\Large This is larger}\\
{\LARGE This is very large}\\
{\huge This is huge}\\
{\Huge This is very huge}


\[ \int\limits_1^\infty \frac1{x^2}\mathrm{d}x=1 \]

\end{document}

