I apologize, a very demanding work schedule has delayed my response to you. Interesting, I had forgotten about the Drew Daniels system, but read it a few years ago; thanks for bringing it back to my attention. To answer some of your questions: the midrange drivers are the aerogel version of the Audax PRO 7 inch drivers; a very rare and now discontinued item. The tweeters are Stage accompany 8535.
I have done some serious thinking, and am going to stick with just two 12 inch drivers per channel for the 60- 250 Hz range. As far as I know, the loading application has not been done before; I call it a reaction cancelling waveguide. For certain, a picture is worth a thousand words, but, it will be many many months before this can happen.... you see, the so-called listening room has not even been purchased yet!! I found one that might work, but it's a built in 1955 home, and have yet to learn the details of how updated all things interior might be. The 12 inch drivers will be the Emminence
Definimax 4012HO. Thanks for your interest.