I've always used CopyII+ for formatting drives, but mine are all IDE, so I'm not sure if you need to do anything special for SCSI. Once you've got it formatted just copy over PRODOS and BASIC.SYSTEM and you're good to go.

Bear in mind that the Apple II scans the slots from highest to lowest at startup, so if you want it to automatically boot from the HDD you'll need to put it in slot 7.