Naniwa Work Stones, Super Stones or Chosera? I understand that the work stones are the softest, chosera the hardest. For beginners like me, soft stones are more prone to accidental damage ("cutting" the stones). The Super Stones and Choseras are roughly the same in price, since the Choseras also include a Nagura stone. The Work Stones are much cheaper. Which should I go for?
Alternatively, stones from Tojiro, Chroma or Kai.
Also, the Nagura stone is pretty small, and obviously flattening is easier with a larger stone. This here looks good? http://www.edenwebshops.de/de/pt/-naniwa-grober-abriebstein-koernung-24.htm
Or is a smaller one (though still much larger than the Nagura), like http://www.edenwebshops.de/de/pt/-naniwa-abritzstein-koernung-24.htm
, at less than half the price sufficient?