How can I test and apply certain changes to all documents in a book file?

Question

I have a book file with around 75 documents amounting to 1927 pages. All of these documents contain the same paragraph style 'Body'.

My first question is:

How can I "test" a change in 'Body' to all the documents in the book file? For example, I want to change font size from 8 to 9. How do I tell InDesign to try this change on all the documents and then calculate the total amount of pages I would get without actually applying the change?

My second question:

After I'm satisfied with the test, how can I then apply the changes to all the documents in the book file?

My end goal is to change all the Body text to font size 9 but also to reduce the total amount of pages to 1850 or fewer. Therefore, I have to find a way to compensate. What I wanted to do was: increasing the size of the text box on each page (reducing the margins).

This bring me to my third question:

Can I change the size of the text box on the master page in such a way that it will increase accordingly on every normal page without erasing the text in it? If so, can I then test this change on all the documents (question 1 but for text box size) to see how many pages I'd end up with and then apply the changes (question 2)?

Thanks in advance for your answer and I apologise if anything is unclear. Please ask me to clarify anything if needed to formulate an answer.

Edit: I've found a way to GREP all of the changes except editing textbox size. I can open all of the documents in the book file at once and then CTRL+F a change (for example changing paragraph style to a bigger font size) and search through all the opened documents. I'll still have to find a way to edit text boxes in this manner.

Answer 1

As far as I'm aware...

There is no "test" ability in InDesign.

You would need to alter the Paragraph Style, then alter each page accordingly. That is, all the text would update with a style change (if there are no overrides in place). However, InDesign won't calculate total pages and will merely change the text. This typically results in overflowed text on the last text frame of the document. If options are set to auto-add pages, InDesign may add additional pages to prevent a text overflow. So, in that instance you could see how many extra pages were added. But if the goal is to reduce the number of pages, auto-adding additional pages may not be the best option.

Changing the size of a text frame on a Master page will have no effect on text frames residing on Document pages which have been filled with text. Altering a master page text frame will only alter text frames on new or unused/unlinked document text frames.

In short, there's no easy solution which I know of. It'll take manual effort to alter frames on pages to fit smaller margins due an increase in type size.

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But, then again, maybe someone else knows a trick I'm not aware of.

Answer 2

My tactic for the 'test' would be to copy all files, including the book file, into a separate directory and play around with everything in that 'sandbox'. If it turns out that your experiment is successful, this 'sandbox' becomes your new actual working directory.

There is something important to note about text frames on a master page. Even though you Ctrl / Cmd+clicked one to override/release it in order to be able to fill it with text, it will still obey changes you make to its template on the master page. Just edit the text frame on the master page, and all pages with that frame obeying that master will adjust.

I have too little experience with book files (especially as huge as these) to be able to say for sure how you'd have to change this in every separate file's Master. Then it's way preferable to doing ever page by hand.