C&G vs Covenants... Did I miss something?

Covenants pp66-67 describes covenant craftsmen reducing covenant expenses based on whether they belong to a common or uncommon class of craftsman. Common craftsmen are described as "those found in almost every village of any size..." and Uncommon craftsmen "are encountered less frequently." It seems the rarity of the craft type is important to the covenant finances.

I was hoping to see something about this in C&G. About the closest thing relating to how common a craft might be is how many guilds are found in towns of various sizes (p54), as far as I can tell. Is there any place that designates the rarity of craftsmen? Do I need to argue with the troupe everytime we recruit a new crafter to the covenant as to how rare the craft is?

Rich