I don't like that their website doesn't mention what you have to write-in. On my Colorado ballot the names were like "Kamala Harris / Tim Walz - Democratic Party". But there wasn't enough room in the write-in box to use that format for PSL so I wrote it like your comment.
For Illinois, the digital version was all capital letters so no worries about case sensitivity there. There was also no way to vote for VP if you were writing in