To install Mac OS off of a restore CD for a different model...
1) Insert the CD,
2) Navigate to Configurations --> Disk Images (I think)
3) Mount the disk image
4) Copy over the system folder from the disk image to your hard drive.
5) Bless the new system folder.
6) Voila!
I used my old iMac's software restore CD to get OS 9 onto quite a few other computers, so I know it works. And I don't see any reason why it shound't work w/ OS 9.1 & a PBG4 CD.
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Be Happy.