Thomas, pardon for butting in here.
Both proposed sailcloths will work, but I would no doubt choose the lighter one at 172g/m². This will inflate and set better in very light winds.

Camber.
More important is that you make the sail with camber in the panels. A sail with camber in it will perform a lot better than a flat one.

I suggest you let David specify the construction of the cambered panels. The challenge is to make the sailmaker follow David’s instructions...

Arne

Thanks David, I've just scaled the sailplan to 24m², it gives something like that :

The mast is very long, I'd liked to make a birdmouth wooden mast but perhaps it will be too heavy.

Hello, I've just bought a Primaat 24 in need of restoration, without a rig, and of course I want to put a junk rig on her. She's a 24ft plywood boat, approximately 1.1t of displacement. Not sure exactely what type of rig I want, perhaps a weaverbird style, 24m² (the same area as the original rig).

I have a bit of work before starting the mast step or the partner, but I've started to think about the conversion. I hope you will help me with the rig !