Both cleats require bevels to achieve a good fit, and this turned out to be a time consuming exercise.
I wanted to be sure that the cabin roof would be properly and soundly secured to the tops of the Dorade boxes, so I didn't mind the extra effort required to achieve this.
Here are the cleats test fitted in the port box.
When I had made the Dorade box cleats I test fitted them and all the cabin roof cleats once more. Here they are.
I adjusted the fit of each cleat until they all lined up nicely and then marked in the line where each would be glued in place, leaving sufficient stock projecting above the bulkheads to be planed away to achieve a tight fit for the cabin roof.
Finally, I glued them all in place, as here.
I left them to cure and wondered how difficult it was going to be to fair them all.