I've never heard of using Inkscape for layout. I think of it just as a vector drawing tool.

InDesign is certainly the standard.

Things got complicated because I needed to output an interim version of the book and wanted a format collaborators could work in. Plus I thought I'd save having to re-layout the book after editing. Which of course didn't happen that way.

Lesson for next time is either live within Google Docs limitations or do layout in a proper tool only when content editing is 99.9% complete.