Considerations when converting plan to skin on frame

[gonzo]

Absolutely, I envisage a double ender, as easier to create structural strength for a mast near the bow, and the lug will keep the forces lower. I think I'll experiment with a dagger board but also some of the old British boat designs used a long rudder that followed the angle of the stern post and tilted under the hull which may be worth a shot too.

In regards to converting the actual lines to being more suitable for SOF though am I missing anything?

You are trying to make a salad of several completely different designs. For example, the boats with canted rudders that go forward almost midships are very heavy and need to have a fairly deep draft; the complete opposite of the ultralight which is your stated goal.