I did something similar - see https://kbin.social/m/RedditMigration/t/65260/PSA-Here-s-exactly-what-to-do-if-you-hit-the (though I didn't have the benefit of the archive). TTThe other thing to look out for is that I'm not sure if you can delete comments or submissions from private subs.,, but you can at least modify the script to warn you about those ids and then you can monitor and wait for the sub to go unprivate (or as the mods to add you to the approved users list)