This is the add-on I've been looking for! Rated 5 out of 5 stars

Beautiful and neat options menu; video centreing works beautifully and many more features which are relevant to what I need.

I have tried a few other add-ons for YouTube on FireFox and this is by far the neatest and best!

This review is for a previous version of the add-on (2.0.1.1-signed.1-signed).