It doesn't work good.
It will get you very sick and alcohol will out do valerian and kava.
Valerian and kava aren't even that strong, and are more of mood enhancers rather than highs. Where as benzo's produce an actual buzz, and in larger quantities an actual high.
Also mixing alcohol with kava can give bad reactions.
And valerian on it's own gets you sick, especially at high dosages, like kava.
If you decide to try this combination, be careful and get some anti-nasuea ready to go.