boat_alexandra - where in South Africa
are you? I'm in Richards bay, heading to Cape Town
with the next weather
window - and would be happy to look at it for you (I'm a sailmaker).
In general, I'd say it's not a recut that'll end well - but depending on geometries there is a small chance you could make something of it.
Jman - crosscut sail seams are not designed parallel to the wind. They are perpendicular to an imaginary straight line between head
and clew. This is so the fill yarns align with the highest load path along the leech - of course leech hollow or positive roach complicate load paths, so it's safe to say crosscut sails
do a poor job of aligning yarns to load. Your point is correct though in that recutting a mizzen to headsail is likely to result in bias loading the cloth - not good. Still, there is a small chance of recutting if the new sail geometry can layout in existing geometry within a reasonable margin of misalignment.