Userscripts.org

little change to your code,

look for this var vlc_controls = new VLCcontrols(myvlc); \

under this add this
vlc_controls.options.set("aspect-ratio","16:9"); \

so it will look like this

var vlc_controls = new VLCcontrols(myvlc); \
vlc_controls.options.set("aspect-ratio","16:9"); \

this will make all videos on youtube 16:9

if you hate the 4:3 ratio :)

great coding