Timbo, thanks for your reply! We were working on the 2nd option, in which the spin halyard is also pulling out the spinnaker.

So it's clear to me to tie it with one end on the tack corner of the sail, run it thrue the pylly on the end of the pole, than to the double pully where it's connected to the spin halyard.

But where does the end of this line go to? Where is this end attached to? Or is it in this case also the purpose to deead end it at the beam?