Hi Mitchell -- I've got the same (old) card and a Nanao 550i monitor.
Try using these 3 cmds for info:
1) % SuperProbe
2) % X -probeonly
3) % X -showinfo
I'm still completing my Slackware installation, but got X
to work, miraculously, the 1st time. After getting info
from the FAQs, HOWTOs, 1) - 3) above, and the
hardware manuals for card and monitor, I ran:
% xf86config => XF86Config (an ASCII file).
Double check it for monitor settings (horiz & Vert rates),
and follow your instructions. The book by Welsh
and Kaufman, _RUNNING LINUX_ was a big help to me.
Cheers, Steve Parker