I finished the layout! Whoo! And it's 374 pages, so that's good, too. I am going to print it out and give it one last go-over before I send it to the printer, but as I've said, the layout is so much easier with narrow margins, I doubt I'll have to fix much. With the wider margins I had to print it out and go over it twice, with fairly substantial changes made both times--and of course the new changes would screw up the old, which was lots of fun.
It's funny because of course I found typos, so I fixed them, but you know, the large-print edition has already been printed, and nothing that I've found so far has been serious enough to warrant trashing that proof and doing another one. So both versions will be slightly different from each other. Likewise, the people who bought an e-book early on have slightly different versions of the book, and the Kindle and Nook versions are going to differ from the Smashwords version, because it's harder to update Smashwords.
I do think now that it's worth it to hold back on releasing e-versions until the layout is done. But the large-print and regular layout are probably always going to differ slightly from each other, because I have to make corrections in Word and then convert it into a PDF file to go to the printer, and Word is just not stable--when you close and open Word, it will shift lines around from page to page, and that's a real pain in the ass when you're trying to lay out a book. So, I just have to be relaxed about it.