Just sharing this: The Adaptec Power domain AHA 2940 SCSI PCI card does not appear to boot on Quicksilver 733 ( much trial and error) or apparently on Digital Audio G4s. My 2003 MDD does recognize it however.
Tried the same card in both machines: Worked in the MDD not the Quicksilver. Then spotted this:
"Not sure what your exact issue might be but I know for a fact that some of the later G4 towers had issues with SCSI cards. Specifically Adaptec cards.
If you look around on xlr8yourmac you will find something. I remember it being the Digital Audio and QS that had the issues."