In MP3 Tag Studio you have the option to write to v1 v2 or both

For an individual song, yes, but I don't see how to do that for several thousand.

The tab labeled "Auto tag (from filenames)" only seems to write to v1 and when I right-click a folder (or group of files) and select "Retag assumed format: <Artist> - <Title>.mp3", it adds both v1 and v2. Then I have to go back and delete all the v1s.... haven't found a way to do that without using a seperate program.