Thank you, glad it helps. Two more metadata points from the NIP-17 text that might be worth a line in the series:
1. Your DM inbox relays (the kind 10050 list) matter. The spec says relays SHOULD only hand gift-wrapped messages to the person they're addressed to, using AUTH login (NIP-42). A relay that doesn't do that lets anyone fetch the wraps and see who receives messages and how often. So pick inbox relays that require AUTH.
2. The timestamps on the wrap are randomized up to two days into the past, which hides when you wrote. But the relay still sees your IP address when you connect, so for higher-risk readers, Tor or a trusted VPN is the missing piece.
https://github.com/nostr-protocol/nips/blob/master/17.md
