How Do I edit/create customised page formats in Lightroom 4 Book module?

Question

Better still, how can I import page formats already created in Blurb's BookSmart program?

Answer 1

You are not doing anything wrong - except to try this in the Lr Book Module.
The Lr Book Module is not a full fledged book layout program, and many things that you expect for a book layout program can't be done.
I would not be so "picky" as to wanting to avoid any up- or downsampling.
But if you absolutely have to, use Blurb Booksmart or Adobe InDesign to do this. In Blurb Booksmart you can design an image box to exact dimensions in inches.
In Lr you cannot do this, a feature that many users want but it seems that Adobe is adamant that templates is the way to go. Lr 5 beta has not changed this.
You can download Blurb Booksmart free of charge from Blurb's website. You will like the freedom of page design that Booksmart offers.
Disadvantages: Your workflow is more complicated than using the Book Module in Lr. And you are bound to print with Blurb.
With Booksmart you have to export the images from Lr to a specific folder from which Booksmart loads the images. But every time you change an image in Lr you have to export it again and load it again in Booksmart.
If you also use the Blurb plug-in for Lr you can create a Blurb Publish Service. Changes to an image that has already been published have to be re-published in Lr but the changes will "carry through" into the book automatically.
Finally, I question whether you can actually test the size of an image in the Lr Book Module by printing the page with your printer. There are reports on this forum that the printed image size is not exactly as shown in the Lr Print Module. I have observed this too with my printer. Mostly the printed image is about 1/8 of an inch larger than in the Lr Print Module. The reason might lie in how the printer translates pixels into ink droplets - just a guess of mine.