% reduce font size and use sans-serif for atoms
\renewcommand{\printatom}[1]{%
\fontsize{8pt}{10pt}\selectfont{\ensuremath{\mathsf{#1}}}}

% reduce bond dimensions to match smaller fonts
\setchemfig{
  cram rectangle=false,
  cram width=2.5pt,
  cram dash width=0.4pt,
  cram dash sep=1pt,
  atom sep=16pt,
  bond offset=1pt,
  double bond sep=2pt
}