About a year and a half ago, I used the Super Find Change script to update a rather large book (<10000 pages). The book update feature never worked, but I worked around it by opening groups of 10 or so chapters at a time and running SuperFind on them. It worked well, even though I couldn't do too many at a time.
This week I opened up the script to run on some chapters but it will only focus on a single file. I've tried every variation of opening files or selecting them in the file list navigation pane, all to no avail. Looking at the blog post linked above, I can see that a few people have had a similar problem. However, I can't find anything where someone has resolved this issue.
Is anyone able to use the script to update multiple chapters simultaneously in a book using Frame 2017 184.108.40.2061? If so, can you walk me through what you're clicking? I'm pretty sure I know what I'm doing, but maybe there is some crazy step I'm skipping.
And I'm about to recommend a Rick Quatro script again, because he has one that I think will do what you want. It's called Find/Change Formats Batch. I've used it to update a number of documents when our naming conventions changed, but you can also use it to change one format to another. Admittedly, none the size you're talking about, but I suspect the only difference would be it taking a bit longer.
It's a trifle more intensive than the script you linked to because it's meant to update lots of formats across lots of files, but it for me so far it works without fail, and you say that Super Find Change doesn't.