HDToolbox is the tool to use. Upto 128 GiB / 137 GB disks are supported on 3.9 without additional tweaks.
Actually up to 2048 GiB / 2199 GB disks are supported by HDToolbox (any version).
It's a matter of drivers which harddrive size will work or not. With SCSI all 2 TiB should work. 128 GiB is a limit of IDE (LBA28 vs. LBA48) which does not apply to SCSI.
OS 3.9 comes with drivers for Commodore hardware only. Therfore using 3.1 or 3.9 does in no way influence the CybPPC harddrive limit.
