I'm a firm believer in you get what you pay for when it comes to classes and training. You can either choose for a basic run of the mill "CCW" class or a focused handgun training class. The courses designed around the NRA basic pistol classes are good for what they are, but they will give you the bare bones of necessary information to legally carry. It's one of the reasons I structured my Handgun Level 1 as a 10 hour class, and I don't even feel like that is enough to give students what they really need to know. Talking to gun shops, even good ones, can only give you so much. They likely don't have extensive experience with every holster or gun option out there. Seek out additional training from a reputable instructor. In my experience, the advantage of talking with instructors is that while they too haven't used all the different holsters and carry guns out there, they have likely seen the vast majority come through one of the classes. They see what works and what doesn't. What gear or guns cause issues for the shooter and which ones function without a hitch. There is no one perfect source for all the information one would love to have.