You may want to think about insurance costs this way. Each company
will want to charge a fee that their experience indicates will provide
them a profit.

They have data and experience across many pilots and many airplanes,
they roll the statistical dice, and hope their bets are good ones. You
can argue theory and 'it-ought-to-be's' for ever, but in the end as an
individual you're going to either buy a proffered policy, or not.

You are really too small an account to have leverage or to have a
Lloyd's 'name' step forward for you.

The reality is, private ownership probably makes sense if the airplane
is going to see something like 250 or so hours or more a year of use.
Less than that, and you are probably better off being a member of a
club or maybe a partnership.

You can surely present your arguments here, but why not do what you'd
have to do in the final analysis and contact the several companies and
ask them for a quote. Further, you might ask what might be done to
reduce the quote.

I suspect it's unrealistic to own a newer hull, or even an older one,
if you expect to fly an hour a week., even if it's between 8 and 9 AM
Sunday.

Let us know how you do when you talk with actual insurers. We would
all like to be wrong about the costs.