Do not flood it with movie scripts and jokes. Flood it with real, plausible names that they have to then investigate. They can filter out jokes, they can't filter out fake data
I got my entire Snapchat gc (15 people) and a little more to switch. The key isn't dropping an announcement of "hey I'm moving", you talk to each person individually; starting with the most likely to switch. Then go up the line, share who you've already got to join if you're met with resistance. if you save the most difficult people for last, telling them almost everyone else is already there is usually enough.
If someone along the way has refused to move for the time being, you can revisit them later after you've got more people to move. I didn't 100% nail my judgement of who would and who wouldn't, but I was able to go back and revisit those who didn't.
If you can, reach out to people in person; I got a few this way. You have to express that you will not be accessible otherwise and will only be present on signal moving forward. It helps if you have a reputation for following through :3
Likely not everyone is going to move over. I've accepted that there's some people I probably won't end up talking to ever again. I've got my main group over, the ones that actually respect that I want more security (and less clown-show shit that Snapchat has)
Human nature wants to stay put, you have to have some strategy or it won't work.
Also a lot of people are pissed at Meta for lobbying for TikTok's ban. Use that with the relevant people, if applicable
Notably in the release from GitHub, not from Play