To avoid having the local hard drives, consider using the NetBoot technology. Here is some important information from Wikipedia
NetBoot is a technology from Apple which enables Macs with capable firmware (i.e. New World ROM) to boot from a network, rather than a local hard disk or optical disc drive. NetBoot is a derived work from the Bootstrap Protocol (BOOTP), and is similar in concept to the Preboot Execution Environment.
A disk image with a copy of macOS, macOS Server, Mac OS 9, or Mac OS 8 is created using System Image Utility and is stored on a server, typically macOS Server. Clients receive this image across a network using many popular protocols including: HTTPS, AFP, TFTP, NFS, and multicast Apple Software Restore (ASR). Server-side NetBoot image can boot entire machines
Mac OS 8.5 and Mac OS 9 use only BOOTP/DHCP to get IP information, followed by a TFTP transfer of the Mac OS ROM file. Next, two volumes are mounted via AppleTalk over TCP on which the client disk images reside. All in all, the Classic Mac OS uses three images; a System image which contains the operating system and may contain applications. Next a private image (or scratch disk) is mounted in an overlay over the read-only System image. Finally, an applications image is mounted. This image, however, may be empty.
If you don't have Max OS X server on hands, consider using BootMania which would provide the NetBoot functionality from a regular Mac OS X box.