>Does it blackjack (unconscious) sometimes?

It does. It doesn't last as long as the blackjack skill does, though, so expect people to wake up within a few hours.

>What are the effect when it doesn't put someone to sleep?
>I get the message 'X' is already dazed from a blow to the
>skull.

Doesn't really have any effect when it fails. The dazed message pretty much tells you that you can't try blackjacking him again until that wears off. It's to prevent people from fleeing until it works.

>Thank you.

You're welcome.