Could anybody help to get an idea how to pass
a spin halayrd + tack line as one? So the crew pulls only one line hoisting the kite.

Route the spin halyard through a block that is attached to the tack line. When the halyard is pulled, it pulls the block back towards the mast, pulling the tack line to it's desired position. When the tack is in position, the halyard (still running through the block attached to the tack line) just hoists the spin.

go to http://nacramania.com/ and you will find what you looking for

Kris

Thanks a lot!
Looks really simple

At nacramania I have seen few pics you sailing kite with furled jib. Does your boat sail faster when the jib furled?