Hi Joerg ,
I don't think that there is much to choose between the two .
However ..........., as a quite experienced Professional ribster / Powerboater , I would seriously doubt the safety of using such a small craft operating alone on voyages such as this .
Please don't just think of your own or your crew's safety but also the safety of those Professional Rescuers who may have to place their own lives at risk in coming to your aid if some thing goes wrong in such a small craft .
We in Ireland have already , in the last 12 months , lost 4 colleagues ( two of whom were also good friends / buddies )after their Helicopter crashed while returning from the rescue of a small ill equipped craft operating in poor conditions off our own coast .
In my opinion ,solo voyages of this nature in such waters should only be undertaken in a well equipped craft of at least 5.5 M
Best wishes ,