preview-tailor

This package provides customization for AUCTeX preview scale based
on the monitor and text scale.

To use it, add (preview-tailor-init) to your init file.  When you
want to change the preview scale for a given monitor, use

  M-x preview-tailor-set-multiplier

When you are happy with your settings and want to save them for
future sessions, use

  M-x preview-tailor-save

See README.org for further details.