This is fun. I needed a test with many different sized PDFs. Originally I tried project gutenberg but it didn't have the variety I wanted. I ended up going to the Anarchist Library which checked all the boxes w.r.t. file size variety and ease of download (as well as minimizing fear of downloading copyrighted material on a work computer)

> the sheet music for 'Still Alive'

Dang. That's just an arrangement for voice and one guitar (or ukulele?). The song pretty clearly includes accompaniment from a cymbal and some kind of metallic pitched percussion too.