No. Simply create a LUN, put it in a storage group as HLU 0, boot the host, press ALT-Q or CTRL-E or any combination you need to enter the HBA BIOS and make sure you set up the boot-LUN in the HBA's of this host (both HBA's !!!). Reboot the host again and enter the host's BIOS and make sure the server will see the HBA's as the first controller instead of the internal SCSI controller.
The host wil now boot from HBA as if it was an internal disk.
No, any HLU will do, but using HLU 0 is cosmeticaly better, since normally you'd start counting with 0 and not with 1. Furthermore: if you're not using HLU 0 at all, you will be seeing LUNz..... A sort of ghost LUN that represents the Clariion. If you simply put the boot LUN at HLU 0 there will be no LUNz.
6GB as boot LUN for Netware ? Really ? I've been out the Novell scene far too long. I loved that platform.