It's listed in the post as "extra credit", but its trivial having done it myself for a client. A bit disingenuous to state, "if you like to do things the hard way." It literally takes less than hour to do, and you can preserve the inventory report for housekeeping if needed.
[1] https://docs.aws.amazon.com/AmazonS3/latest/userguide/storag...
[2] https://docs.aws.amazon.com/AmazonS3/latest/userguide/batch-...
(OP: feel free to steal this comment's info if you want to update your post)