;-) From my experience, one thing to watch for when using hard drives larger than 4 gigabytes is to make sure that the boot partition exists wholly inside the 4 gig barrier.
Also, AmigaOS3.9 has built-in drivers that allowed me to use an 18 GB SCSI hard drive on my CyberstormIII without trouble.
:-( -up until the day that my old A4000 died, that is....