
\documentclass{testsuite}
\usepackage{fontspec}
\setmainfont[Color=FF0000]{Georgia}
\def\1{abcABC}\def\2{XYZxyz}
\def\test{\1\textsf{\2}\1\\}
\begin{document}
\setsansfont{Verdana}
\test
\setsansfont[Scale=0.5]{Verdana}
\test
\setsansfont[Scale=MatchLowercase]{Verdana}
\test
\setsansfont[Scale=MatchUppercase]{Verdana}
\test
\end{document}