gentoo-overlay/x11-themes/silver-xcursors/files/README.gentoo

To use this set of cursors, edit or create the file ~/.Xdefaults and add the
following line:
Xcursor.theme: Silver

You can change the size by adding a line like:
Xcursor.size: 48

Also, to globally use this set of mouse cursors edit the file:
   /usr/share/cursors/xorg-x11/default/index.theme
and change the line:
    Inherits=[current setting]
to
    Inherits=Silver

Note this will be overruled by a user's ~/.Xdefaults file.

If you experience flickering, try setting the following line in the Device
section of your xorg.conf file:
    Option "HWCursor" "false"