How can I set twoside, symmetric layout for bookdown::tufte_book2()

Question

I'm using the fantastic new bookdown package, right off of Yihui's boilerplate, using the bookdown::tufte_book2() output.

The result is lovely, but I'd like the pages to be symmetrical, so that the margins are always on the outside of a two-sided book.

I understand that the original tufte latex package offered this via simply setting:

\documentclass[twoside,symmetric]{tufte-book}

Where do I plug this into my bookdown project?

I've tried just adding it to the preamble.tex, but that didn't do anything.

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Ps.: Please don't shout at me that this is LaTeX question; it's really not. It's an rmarkdown / bookdown question which happens to output LaTeX.

Pps.: Have I mentioned how marvellous and beautiful Yihui's bookdown package this? The future of (academic) (~nerdy) publishing is with us!

Answer 1

Set classoption in the YAML metadata of index.Rmd:

---
classoption: twoside,symmetric
---

For more LaTeX variables, see http://pandoc.org/MANUAL.html