I just spent ages making a new 200 song playlist (would be great to be able to duplicate a playlist, edit & select mutiple tracks at a time to speed this process up a bit), and pasted the new code into the page:
Thanks for trying this. Sorry it's a bit late but if you drag the playlist to '+ New Playlist' it'll duplicate it for you. You can also hold shift/control/command to select multiple tracks just like other files.
I'll let the right people know about this one. Just as another quick test, do you have any problems with an embed made of, say, 10 totally different/popular tracks?
Thanks for your patience here. We'll update you as we learn more.
Edit: Please keep this playlist on your account so we can prod at it.