well then there is an intermediate way - getting your hands dirty on editing config files, there is happened to be one for X believe it or not. It is /etc/X11/XF86Config-4, first make a backup copy in case you screw the original
as root in console
cp /etc/X11/XF86Config-4 /etc/X11/XF86Config-4.orig
now open the file in a text editor, you should see the lines
change 24 to 16, save the file and try running X.