I have used the Jaz method my self, and it works fine. I even bought a couple of extra used drives and added one to the pc just for that purpose (file sharing). Haven't tried networking yet.
You can put 2 scsi controllers in one Amiga. Each will be it's own chain. Each will have to be polled seperately. Each will have a unique tooltype in harddrive toolbox ie scsi.device, warpdrive.device, omniscsi.device ect...
