Just a few comments on this issue.
First - as in anything else in Socionics - nobody is going to behave according to Reinin dichotomies all the time. Nobody is going to be consistently, say, Taciturn or Narrator all the time. This is obvious, but it is worth stating again.
Second, in my opinion and observations, the most correct interpretation of how Reinin dichotomies really work is that put forward by Smilingeyes especially in his behavioral tracker - they are more or less fluid along the temperaments. Especially the Narrator/Taciturn, Process/Result, Negativist/Positivist are very fluid. It is more useful to see how they "move together". So for instance, if someone very often displays the Negativist-Narrator behavior that is most typically associated to INTps, that is a good indication that that someone is an IP or EP, since in those temperaments that's where that combination happens, and probably not an IJ or EJ. In the absence of any other information, it would be rash to be more specific than that.
Third, Reinin dichotomies are a tricky thing. It's easy to see in yourself the behavior of any of them. So if you want to use them for typing, you have not only to be totally "relaxed" as to which ones you "want" to see but also understand them well.
To use again another example I keep referring to -- when Kristiina thought she was ENTj and many were arguing that she was ISFj or ESFp or even ISTj, she used the Reinin dichotomies in a straightforward, yes-or-no way. As a whole, they pointed out to Beta NF, the correct answer, much earlier than any other method. That happened because Kristiina wasn't too concerned about the results going one way or the other.
But if you are already trying to prove this or that type, they are much more sensitive than other Socionics points to the Forer effect.
Someone very skilled in them - I would only include Smilingeyes in that, not even myself - can use them well to type others, by observing their behavior when they are being "themselves".
And this is not an argument I have just adopted I have held these views for quite some time.