Search:

I haven't found either of those to be the case. Hand rubbing cleans them quite well. And they get harder as you go up in grit; I've only had problems with dishing on the 1k and under.

I'd think you could get 4 if you cut the full hones in half both ways.

For travel uses, I would assume you want tuchups and minimal maintence? If that is the case, I would go with 8/12 or 5/10.