Hi, I wrote this post, and I just wanted to say thanks for the kind words - this research was a lot of fun to do and I'm glad it has an audience.

The "best" resources I know of are the ones I cited in that post, though do bear in mind it's a few years old. That said, I did want to make sure you didn't miss this companion piece: https://eli.sohl.com/2020/06/05/dht-size-estimation.html which is applicable to detecting (and - conjecturally - responding to) Sybil attacks.