Self consciousness =/= narcissism IMO. A person might be self conscious for many reasons.

I don't think you can really get at the underlying reality of what you're trying to explore if you use words like "narcissism". I'd take a step back and look at Cluster B personality disorders as a whole to get a better idea of the clinical dimension of "narcissism" in a broader context, and to dissociate the popular meaning from the clinical one. There's general deficits in emotional processing, the ability to take the perspective of others, and various vmPFCish thingies of that nature, and sometimes those present in a certain stereotyped fashion labeled "narcissistic". I'd characterize it as more a deficit in self awareness and other awareness, with the rationalizations filling in the blanks left by that deficit sometimes but not always creating an inflated self perception.

how to spot the narc and how to figure out you are one or not: again, focusing more on the less obvious, shy-type, insecure type narcissism,

Rejection sensitivity, abnormally harsh self evaluations and feelings of inferiority can also fall into Cluster C, especially "avoidant", and depressive states. I think the difference is that with Cluster B, there is at least some level at which a person is trying to defend a positive image of themselves even if they have deep-seated insecurities. There might be periods triggered by negative external events causing them to express some extremely negative feelings about themselves (which they later recover from and can be talked out of) but for the most part they like themselves. In contrast, an anxious, avoidant or depressed person just consistently insists that the low self evaluation is correct and it's much harder to talk them out of it.

I think the briefest way to say it is that Cluster b is associated with basically normal emotional states, but those emotional states do not react normally to environmental cues, and the specific abnormality is what further characterizes them.

In the stereotypical and stigmatized case of narcissism, a person fails to accurately self monitor their own behavior and model how others see them and response to that by constant negotiating status, and if this is paired with a small degree of antisocial personality disorder they might also give more relative importance to themselves due to empathy gaps. The reality is probably more complex, with some people really caring about others but still lacking the ability to model how others view them, and so on.

(Bewarned, these are pretty arm-chairish thoughts. Then again, the DSM is pretty arm-chairish too.)

Another thing I would be interested in is social media

Relevant to your interests.

I suppose I just went ahead and discussed in the clinical sense even though you particularly didn't want that.