What about running the Ancora sealed? I know it’s a three way and little down in the 92 dB target but it could be a good option.
I've got an Ancora from Rick, and it does sound great. It's sealed, too. However, you are correct that it is shy of your goal of 92dB.
Have you considered an MTM speaker? It would be easier to achieve a higher sensitivity.
Until this post, I had been lurking on this thread. I may just be interested in whatever is decided upon - especially if it becomes available as a kit.