Awesome Spoons!
the big cheese - I wouldn't use rock salt; I don't think its salinity is the same and it's a bit unpredictable in my opinion. Also takes longer to break down which is important when you are trying to make brine or direct-salt cheese.
Kosher salt is VERY easy to find, most supermarkets carry it. It's a coarse salt and it has very balanced and clean "salt only" flavor. It is used in so many recipes because it dissolves so well in liquid (even if you don't boil it) and because it's not iodized. (Iodine in salt can kill off desirable bacteria in cheese aging, meat curing or pickling).
In spite of its exotic name (it's the type of salt use for the koshering process of meats) it has nothing to do with being Kosher (and often isn't even kosher certified) and you don't need to find a kosher store for it. Kosher pickles too are often not kosher at all but are just called this way because the brine is salted with kosher salt. When you get Kosher salt, always try to get one that doesn't contain anti-caking agents. Just pure salt. I use the Diamond brand. If you can't find Kosher salt, just use table salt that isn't iodized and has no anti-caking additives (cellulose, silicone dioxide etc.) You can also get "cheese salt" from the same place that sells you your cheese cultures. I think it's just a finer ground version of Kosher salt (I think)