ATi Rage 128 on Powermac G4s

We're using some old Powermac G4s as our Gateway machines for both our old and new clusters.  The issue with these machines is that they have an ATi Rage 128 card in them, and they are notoriously finicky in Linux.  I found this site helped tremendously:
http://www.jonh.net/lppcfom-serve/cache/1043.html

Our final yaboot start?

linux video=aty128fb:vmode:20,cmode:32

Failure to do this will result in the monitor shutting off shortly after boot.