So, I used @pruvisto 's Debirdify to get the Mastodon addresses of everyone I follow on Twitter.

Then, I downloaded those addresses as a CSV, which seems to be in a format used for interchanging AP addresses in Mastodon instances.

Then, I went to Preferences -> Import and Export -> Import, selected "Import Type" to be "Following list", chose the CSV file I'd downloaded from Debirdify as "Data", selected "Merge", then the "Upload" button.

It worked well! ~14% of my Twitter follows imported.

@pruvisto @evan how long is it supposed to take? is it delayed until the server is less busy?

question from another user : https://mastodon.social/@matthieu/109372321639235564

@chris_mahan @evan If you're talking about the input: I have no idea. I don't know how any of that works. But I have heard from people for whom it really does take excessively long. Like, days.
@pruvisto @chris_mahan @evan I know on the server I've just migrated to that there is a big job in the queue being processed so "niceties" such as bulk imports are being delayed (it's been about 3 hours). When I was doing imports on mastodon.social it seemed to be less than 10 minutes per time.