Thanks guys for the feedback, this is helping to decide.

Hi Luke. I have just checked one of the hulls and it definitely has a hull doubler inserted. Although larger and not glassed on the outer edges.

The newer timber hulls seem to be using a second half bulkhead frame under the forward beam pad.

The mossie that I have I think originally came from the Gippsland area. (Someone surnamed Wilson ).

At this stage I'm leaning towards the round (dunny ring) type.
Thanks Dave 1724.