Restore old Youtube Layout | Upgrade Old Youtube To New Setting

Hello, I have 3 linked accounts on youtube, my personal account and two channels. On my personal account I have the new layout, on the two others I get the old layout. I am not able to see the option in TestTube on any of my accounts. If I am able to see the new layout on one account, how can I make the other two able to see it too? Go to youtube.com and press F12, then go to console and type document.cookie="PREF=f6=4;path=/;domain=.youtube.com"; press enter and reload the page. worked for me