Not every rule can be written. It's just impossible to write everything into the rules that needs to be a rule. To allow recipes to be posted publicly would first be a spoiler, and second would ruin the value of the books they are contained in, and some of those books are really valuable. Not all recipes are contained in books, though. It is fine to discuss with friends through rmail.
I don't know of any way to see a ratio of ranchers to merchants.