I've sewn a patch of Odyssey on either side of my damaged area, tying it into the leech tabling and the peak reinforcing patch (which is quite substantial). The damaged area was about 50mm below this reinforcing patch and parallel to its lower edge. I was able to tear it with one finger until I got to the end of the damaged area, after which the cloth seemed strong. I've never been able to tell how strong my sail is as the material is so alien to my experience. It is so light and soft, and when the sun shines behind it, it looks porous! You almost need sunglasses to look at it! Having never looked at the material before telling my sailmaker to use it, I was quite shocked when the sail arrived.
Because I have decided to remain in Broken Bay and adjacent coastal waters this summer, I will just watch the sail and see what happens next. If I was going to go offshore, I think I'd either bend on my flat Dacron sail or think about a new sail.
I think any problem lies with the material rather than camber in the sail, at least with these H/M type sails. The first thing my bermudian friends say, when they come sailing on Arion, is how lightly loaded everything is, compared to their rigs. Perhaps the peak and throat are exceptions. I tore the throat of my sail the first time I went sailing, when I was lowering the sail and Arion rolled violently, allowing the yard to surge back and forwards. I then substantially strengthened both the throat and peak. These days I run the YHP and the THP through rope clutches and keep the slack out of them as I lower the sail, which keeps the yard under control. It seems obvious that a flat junk sail will spread the loads more evenly, however even a cambered sail spreads the loads out over all its battens, unlike a bermudian sail which concentrates loads at the tack, clew and head, or throat and peak in a gaff sail. And as Arne points out, our sails have little load on the tack and clew. Perhaps Topgun is a more suitable material, being heavier, or acrylic, or Dacron, if you keep it under a cover.
I am happy enough to experiment inshore, but if my health permits me to sail offshore again (the eternal optimist!), I want a rig that is reliable! If the sail was easier to rig and unrig, I'd have two sails, a light, cambered one for inshore work and a heavier, vertical seamed, flat sail for offshore. There is no doubt, having sailed with both types of sail on Arion, that my cambered sail makes the boat come alive when sailing inshore in light winds and smooth water. Arion is an absolute joy to sail in these conditions, tacking confidently into crowded bays, ghosting along in the slightest breezes. I am willing to keep experimenting for that reward.