Often when I go bargain hunting for books with interesting paper - I like to use fountain pens and mechanical pencils, which don't always like the same paper, and prefer smaller grid-lined (smaller grids) formats - some of the more interesting stuff I find is in paper sizes not standard to North America (A4, A5, B5 and I even have some B6 sized books that have pretty sweet paper for fountain pens).

I had to find binder hardware to make my own B5 binder because I couldn't find any I liked (and nothing locally).

And then finding refills for other books has begun to look pricey or challenging. (Anyone ever see a notebook cover for B5 or B6?)

So if I'm going to buck up and order online, to boot, I'd rather have an idea of what I'm getting.

So what are you using, refill and binder-wise?