Select a youtube resolution and resize the player.
I'm glad you like the script. I do want to support premium bitrate, but as mentioned elsewhere I do not currently have youtube premium so it is difficult for me to develop and test. Until then, you may want to consider giving a try to some of the alternative scripts available, such as: https://greasyforks.org/en/scripts/498145-youtube-hd-premium
Really great script! It would be great if it supported 1080p Premium as well - I see in the script that there is a section that mentions Premium, but it doesn't seem to work, no matter what the settings are, Premium 1080p is never selected.