First things first. GVP's tools SUCK, it's waaay to old. I gave up on it a long time ago. If you can find any excuse to reformat the drive use HDToolbox, specify in the icon tooltype "scsiname", on my GVP 060 its "tekscsi2.device" this will allow HDTools to "see" your drive. Go from there.
Please note & be carefull to use correct MAXTRANSFER & SCSIMASK to have good speed, reliable operation & full mem access.
From an old 2000 user
Chris