One might think that this would be easy as tweaking a few settings, but no ... while the lay-out for the .PDF version was full-on centered on the page, to accommodate the paper mass of a 400+ page book, I had to shift everything to new margins. Since my header and footer material were set to the outer page margins on both the recto and verso, I fortunately didn't have to change the "master pages" in MSPublisher ... however, I ended up having to manually adjust the text box on each page, pulling the inner edge out of "the gutter" by more than a third of an inch. This, of course, then changed the lay-out on every page and the text was now flowing through a somewhat narrower space.
Of course, when setting up the ebook edition, I'd poked and prodded and nudged line spacing to make stuff fit as well as possible (avoiding "widows & orphans", etc.), and all that coding was also in the new version, meaning that I had to pay particularly close attention on how paragraphs were lining up in relation to each other. To my credit, I got MOST of that OK on the first go-through, but it was amazing how much stuff turned up every time I did another read-through.
First I did the edit and saved the .pub file off as a .PDF that I could upload to CreateSpace ... in my review of that I found five errors, some as simple as having ascii quotes in one piece (instead of "styled" quotes), and graphics that hadn't been centered in the new margins, etc. I figured I was good-to-go and uploaded that to the CreateSpace service. When they got back to me with the "review" function, I did another walk-through and was shocked to find another 13 things that needed fixing ... from the horrific - a glaring typo in the title of one of the pieces, to a missing quotation mark in a TOC entry, to a few places that needed a return or had one too many, to a couple of pages right at the end where the recto and verso master pages had gotten screwed up.
It amazes me that I was able to miss (most of those, the spacing ones were new) these not once but twice (especially that chapter heading). When doing "check-through" edit reads I usually look for just one type of thing each time through the text, and go through it repeated times to make sure everything right without having to look "for everything" each time on a page. I'm usually quite sensitive to text errors (which is how those ascii quotemarks stood out enough to catch), and so I'm mortified that the error of that title got through (and I need to get back into the free ebook file and fix that, since over 30k copies have been downloaded with the error!) ... but what I'm really amazed at is that I didn't see the pages with the wrong lay-out until the file had been up on the CS system and I was looking at them side-by-side (and, in the online version, with shadowing in the gutter, which made it really stand out). I guess that's why they have those features.
I'm sure that even now there are still errors lurking in there (aside from a couple of widows/orphans that I just couldn't mess with line spacing enough to get rid of, without making the surrounding text look funny), but it certainly makes me a bit more understanding when I run across "glaring errors" in other people's books (especially when I'm reading ARCs - advance review copies).