As another data point, in my also noisy Bonehead I tried the high-noise mic insert. The result is dramatically better voice quality, without the wind noise getting through. Mal (OP) and I proved the difference today by installing my mic in his helmet, with the same improvement noted. So this, for us, is the solution.
It seems there's a bit of variation in quality of the standard mic. Another member of our formation team sounds fine from his helmet, in his equally rowdy RV.
For reference, the original insert is a Pilot PA-7X, and the replacement is a PA-HNM. It also seems to be labelled PA-9EHN in some places.