Sorry, Graeme, I'm finding it more and more difficult to write clearly and at length. It's no surprise to me that you missed the point.
When joining two panels, laying them back-to-back or face-to-face, and stitching along the edge, is a no brainer. Whether the sail is small and light, or large and heavy, this has got to be the easy way, and though it's not standard sailmaking practice, its longevity is well proven. It's much easier than a lapped joint, which is not too bad if the edges are straight and the panels are flat, but gets difficult if the panel edges are curved or if there is 3D shape sewn into the panels (by any method).
But having done that, the difficulties with method B start (for anyone not used to large scale sewing projects, but not necessarily for a skilled sailmaker):
- Sewing straight batten pockets onto the curved edge of a barrel-cut flat panel. Of course, that problem goes away if both edges are straight, as is the case for a shelf foot or a panel that has a faceted edge with tucks sewn in so that the edge becomes straight. But sewing the lapped joint between a straight-edged panel and a curved-edge lens introduces another difficulty. So I would always recommend a tucked edge for ease of sewing method B (and C and D), and for the best appearance of the complete sail - for an unskilled sailmaker trying to sew a large, heavy sail.
- Deciding what to do at luff and leech where there are no pockets - the seam needs to be felled, which can look untidy, and can result in so many layers that the machine may not cope - again, on a large, heavy sail. These issues are trivial in a small sail of thin light cloth.
And so I've proposed
methods C and D, which start in the same way as method B, with one panel on top of another, and with the same ease of sewing those panels together, but with different methods of adding the batten pocket that are easier and better than method B.
- The batten lies closer to the sail, which results in a better appearance.
- The seam is not felled, but protrudes on the opposite side to the batten, where it does not result in having to sew through too many layers.
I know that Arne has said that method B allows for the removal and replacement of a pocket, but I don't buy this. I can't remember ever having done so. Make a good sail, with good materials and methods, and it won't be necessary.
Anyway, whatever methods Paul has used, this is a mighty fine sail, well built and good looking, and I'd be proud to own it and happy to sail it anywhere in the world (if I were a decade or two younger).
I hope that's a bit more understandable.