Disregard. I solved the problem.
I started to think ahead, though. Patching scsi.device solves the problem of not seeing the entire capacity of the drive but what about FastFileSystem limitations? I want to have two partitions that are approx 7GB in size. I'm pretty sure OS 3.9 allows for >4GB partitions but thought I would ask.
I discovered accidentally that I did not have to do all that patching business-- the patched scsi.device was already included inside the MyFiles folder of the ClassicWB install! Oh well.