One option for Beige G3s might be to look at the SCSI2SD v6. They are newer and much faster.I was having some success with a SCSI2SD adapter, but started to have problems with files hanging when we try to open them. We are having storage issues that I was not originally made aware of, so I need the ability to install a bigger drive.
The other thing is for either of these, you want to run the fastest possible SD card you can get. It makes a difference and it should hopefully resolve the hanging or slowness you're having. If you're looking at SanDisk, you want at least an Extreme. They aren't much more and we've seen them making meaningful differences, along with making sure the scsi2sd v6 (in particular) formware is up to date.
On the storage issues front, are you looking at "not enough storage space" or something else? I almost wonder if getting an AppleShare server of some sort is really a better plan than loading all of your desktops with really big SD cards.
The unfortunate thing is that if you need lots of storage space, OS9-based server solutions start to be unfeasible rather quickly, because Mac OS 9 has a maximum volume limit of 2TB.