Algebra to make your own crown binding

I worked out the algebra for crown binding (so you can make a binding to fit your pages if you need to).
Determine the:

• height of the page you want: this is p.
• number of signatures you want: this is n
• the width of what I'm calling the "gutter" (the concertina into which you will slot the pages): this is g

Then cut a concertina which is
p + 2g high
by
g x (2n+2) wide.
divide the page into 2n+2 sections (if n = 3, as in the book, then it's 8 sections)

I'm pretty certain that an odd number for n works best (because it may muck up the mountains and valleys I think?).
From my experimenting today if g = 1cm is a tad small: quite fiddly to fold. It's practical (so far) for holding the pages in though, so if you're a nice neat folder it may be fine.
g = 1.5cm is not too intrusive and it is easier to fold.

The photos below are from my copy of Alisa Golden's Making Handmade Books. (her blog here) and from my notebook.

And here's my next crown binding in progress: It's made from the dustjacket from a book I altered recently.