I started out with the APS (see signature), and was introduced to the Keirsey Sorter II online by a friend. Both my wife and I tested as ENFJ, which sounded somewhat like her, but was way off for me. I saw that the KTS used the four MBTI dichotomies, which I had seen years before, but had never looked into. So now, I was determined to see how MBTI corresponded with APS, and from there figure a type.
I of course looked at descriptions of all the types, but none seemed like perfect fits, and several had traits I could identify with. I realized the dangers of a Forer effect (which I had never even heard of yet, but I knew that any person might be able to identify with descriptions of any type). Just going by dichotomy descriptions, it did seem like a good bet I was N and P, and figured I had to correspond the two systems, if possible, to find the best type.
Already, you had I/E, which sounded like a match for FIRO/APS' "expressed Inclusion" (eI). I had low eI, so figured I must be an Introvert, though Supine is said to have extroverted qualities, so I kept that in mind as well. Both T/F and J/P seemed like good matches for the other dimension known as "responsive" (wanted) behavior. Then, I had to figure how S/N corresponded.
I soon learn about the Interaction Styles, which I determined matched Inclusion, and that the Keirsey temperaments matched the other area of Control. That suggested (INP=Supine) + (NT=Choleric) = INTP, which turned out to fit well, especially from Paul James' description.
From there, as I learned more about the cognitive dynamics (which as we see can often be ambiguous), which raised some questions at times, so it became a matter of ironing out the best interpretation of them. But overall, this all seems to have worked out.