At last. It took four months to do two months work, but at last, the new rig is working.
The mast has to be lengthened, to accommodate the high aspect ratio sail.
It took a long time to work out methods to make the carbon fibre battens, to be light, stiff, strong, smooth...
The sail was the relatively easy part. Flat cut, just big. 580sq ft working area, x 1.5 to give total area to be sewn.
Now comes the payoff for all that work. There are still plenty of things to be tweaked, but the performance to windward is much better, sailing closer and footing faster. Handling is easier than the low aspect ratio fansail, as the chord is two metres less.
Some early photos here.