Q. How would you recommend citing a note which occurs in the front matter of a book on a page numbered with roman numerals? Following the advice in CMOS, my troublesome page reference in the footnote would be xviiin1. Looks odd, no? And a bit hard to interpret for any but the editorial in-crowd?
A. It does look odd. You can prevent confusion by spelling out the abbreviation: xviii, note 1. Using italics for n and nn might help: xviiin1. Regardless, be sure to let your copyeditor in on the strategy.