Shorebird,
Very pretty Honeymoon. You'll need to get a hold of "Boye 10" new old stock needles or MTx190 new industrial needles. Any set of Davis Underfeed attachments will work, Davis made quite a few for their Sears models marked "Attachments", though their difficult to tell apart from other makers by photo only.
The "A9" and "A10" only applies to the Davis New Minnesota A. Davis top leaf tension only use the Davis long needles, they were never redesigned to use the 15x1 even after all the other Davis' switched over. I'll thread up my model n, a smaller similar model, and take some pics later on.
Jon