Most people still have them on Kind 3s. But the new model is NIP-65. I would sent to all write-enabled relays in both lists.
Discussion
The onboarding client i just mocked up will not only use NIP-65 to store user’s relay choices, but will also allow discovery of their friends’ chosen relays.
Social recommendations solves many onboarding challenges, and they all start with the nostr advocate who invited their friends.
This client will:
nostr:note1n56dpv3ck393nz9axmf5j9esnyaj642sfawqne4zs9ufy9865cvqu056gx