Hi Bernd,
Thank you very much your insights.
In fact, what would be great for my needs would be a DUO900S in the same way you did a DUO800S from the original DUO800.
This is a quick sketch of my ideas.
Could the original design for the DUO900 be modified easily to achieve this? I would imagine that the most work would be to define the new sail plan for a parallel rig (junk/wingsail/wishbone).
Alain Dupuis