It worked! I found 150 twitter follows on Mastodon with https://fedifinder.glitch.me/ . It's pretty straight forward.

Click "Authorize to Extract Accounts"
Choose "Scan Followings" or "Scan Followers"
It will create a file for download.
Then open your Mastodon account (I'm on .world so don't know if all are same) Preferences > Import & Export > Import.
Click "Merge" (so you don't lose your currents Follow list) then "Choose File" and upload the Fedifinder list.

Good luck.