What would be a good way to bind a A8 notebook?
I ended up using the coptic binding and it went surprisingly well. The only thing about it is that (unlike the Japanese binding) it needs something to hold the notebook close (but it has 8 x A4 sections, after all). It seems that, being similar to the coptic binding in a way, the section sewn hardcover binding would have also been a good choice. Contrary to what I previously thought, not having special tools does not seem to matter for the final result.