Look into Mexican Cookbooks by Dianne Kennedy. She describes numerous types of chiles as well as wonderful photos and illustrations of what she's describing. As far as authentic, these are important. The combinations are endless and every single one is delicious in its own right. You just have to find the taste you like best.
My favorite regional cuisine is So. Mexico, Yucatan,and Guatemalan. More bordering on the mole variations, tons of flavor and not as much heat. Fire roasted chiles and ingredients, pepitas and sesame seed are a major role, masa flour in the sauces.
Also there's a huge variation in "mexican" restaurants. You have the commercial chains or the hole in the wall (much preferred) family places that have the more authentic flavors. Not as pretty but OH so much better. When all else fails, ask.
Our Guatemalan family was more than happy to explain about the Guajillo, cascabel, ancho and whatnot that went into the traditional Christmas paches tamales. Este y este y este...lovely.
Hope this helps.