Your suggestions worked well with the following issue: Even in the setinterface script you need to set that interface down while changing the MAC address.
Based on your suggestion, I now have a short generic script set into the “pre-boot” which copies anything it finds in /Database/custom/ to the scripts directory. That works really well.
And I did check the backup script to find that the backup file is simply a uuencoded tgz file of the “database” area. Simple enough and very effective.
Thank you for your help! (I’ll undoubtably have other questions in other threads).