Nick, I've been meaning to tell you that I finally cleared some room on my Sony 505 to test this. It works great
! I thought it would take forever to load and navigate but it actually opens instantly to the first page (which, by the way, is blank). On the next page (the table of contents) you usually have to make repeated button pushes to get to the letter you want to select and that takes a few seconds to do. Once you've selected the first letter (e.g., M), the Reader then displays "Formatting...." at the bottom and Sony's equivalent of the hourglass. That takes about 15 seconds or so and then you arrive at your well designed second level table of contents. From there, it takes a bit of time to again make repeated button pushes to highlight and select the link you want (e.g., Mendable), then there's only a few seconds pause again and you're at your destination and usually only a few pages from the word you wanted to look up (e.g., Meniver). In all, the process usually takes less than a minute. All the links work well (e.g., in the definition for Meniver, there is "Same as Miniver" with a link). The only possible discomfort is if you've mistakenly looked up a word in the main body of the 1913 dictionary which is actually in the "New" words section that you've so kindly added. But I've usually guessed correctly whether a word is new or not.
All in all, I find this to be a terrific addition to my Sony library and I intend to keep it and use it often. It's not as seemless as it would be if Sony had added real dictionary support to the Readers by letting you highlight a word in an ebook and push a button to take you to the entry in a dictionary. But without that support, this is the next best thing and I think it's wonderful. I greatly appreciate the very significant effort you made in making it available and I take my hat off to you.