I don't really care if the blackout works or not. Either way Reddit is going to die, the only difference is how quickly. I'm just happy it introduced me to Lemmy which is much closer to the kind of experience I wanted anyway.
As far as I know, it's the easiest to use. Just go to their page, drag the provided button to your tool bar, and then run it on your user page.
There are also options to edit your comments to a custom message and to export your comments to a CSV file. It's that latter one that gives me headaches right now. The export works fine, but due to the blackout, the script can't access my posts/comments on the participating subreddits.