Works very nice! Tried it With ruTorrent and Deluge. Thank you a lot!
A suggestion: Could you please add an option to disable notification about torrent successfully added? Torrent UI sends the same notification itself, and I get double notification. I'd prefer UI's notification only, because it is more meaningful.
Another suggestion: you should write a Youtube downloading addon with opensource backend. *All* existing options are both closedsource and scummy. You will be the king of extensions with those two. Just make an in-browser UI for youtube-dl and ffmpeg.