Thought I'd let you'll join in on this project since I've found the information here of extreme value.
The DDS1 arrived this week from Utah via freight safe and sound minus the Altec 811 horns that are coming from another place. Thanks to the AK design collaborative thread, I was able to settle on Selenium 220it horn drivers and Zilch's 8-ohm X-over with Parts Express parts, very helpful.
I was able assemble an X-over this morning and it was light and day difference from the stock. The stock were almost unbearable, I decided to use only the Seeburgs inductor coils but wired them according like Zilch's design with the new components and the L-pad. Very nice outcome so far! Very listenable and cleaned the boomy bass quite nice. Even running without the L-pad there is no pain!
The massive woofers provide effortless bass, I include a picture next to a turntable for comparison, and there are two in each box.