[newbie] Adequate hd for linux?

[Bob and Christine]

I have PowerMac 8500/180 256 MB of RAM, employ an E651 ViewSonic monitor
for which I have documentation, use an Epson stylus 600 printer, want to
use an external hard SCSI hard drive (500MB), have recently received (from
Carl C.) a YellowDog CD TO BE INSTALLED 19 JANUARY.

I'm told, on the one hand, to use a 1 GB hard drive for best performance,
but, on the other, that SCSI hard drives that big are rare.  Is this OK or
should I try harder?

Bob Trotta