In looking around more, I ran into some more threads on resolution
problems. Xrandr was the theme.
I have used cvt to get a modeline, and gtf. Both seem to produce
reasonable output. To use xrandr --newmode I get an error of
Failed to get size of gamma ...
The followup to xrandr --addmode and xrandr --output both "fail" with
that same message about the size of gamma.
All of the topics I visited, are looking at a computer which has the
installation complete. My installation is just partial. Hence,
anything about editing a file and rebooting don't really work, as I am
booting from a LiveDVD. I guess the next thing to try, is to make a
partial xorg.conf file, and then do a killall Xorg. The LiveDVD is
configured to auto login on start (or restart). I suppose I'll find
that they are not using a writable overlay on /etc/X11? :-)