i'm thinking there's so much personal preference as to which graver and which geometrY for a given material, that there's probably several for each material we all normally work with. perhaps you could hint at a given material you're interested in working on. if there's a "guide" that will answer your question, i'm unaware of it.
As monk pointed out so well there is to much personal choice. I engraved several years with hammer and chisel while using only HSS for anything including gold, silver, copper, brass, steel and even some stainless steel. A while ago i skiped to a palm control airgraver and now i am using almost only carbalt gravers for all kinds of metal.
I use HSS only for gravers with shallow geometry or knive shaped gravers because carbald might break a bit easier that HSS.
Of course if a stainless steel is to hard for HSS you might have a chance that carbald could do the job. But other than that i dont know of any rules to use graver x for material y.