I think that you do need to shop around.
I have life insurance with CIS, and their rep was great - he shopped through the various conditions of different types of policy for me until we found the combination that gave my wife the cover she thought I should have, with the premium that I thought I should be paying. The differences were substantial and it was very necessary to shop around quite a lot.
This is where an insurance agent / rep can really earn their money for you.
In my experience companies will normally have some kind of "aviation activities questionnaire" that covers most potential activities, and will take into account the general pattern of your flying. It tends not to be a one-size-fits-all.
G