I think I might have found the secret to finding your dual.
You have to cross the emotivist/constructivist barrier.
A pattern I've noticed based on this chart is that every dual pair has 1 emotivist, and 1 constructivist.Constructivists
Constructivists try to get into the right mindset for an activity and it takes time for them to get from one mindset to another. When they are at home, they are mentally prepared for anything that could happen at home and when they are at work, they switch over to work-mentality. They can get overwhelmed by emotions because once they get into an emotional state, they stay in that emotional state for a long time. Constructivists avoid emotional contact with others and they don't think it's necessary to adjust to the conversation emotionally. They use automatic polite responses and customs, like starting with "how are you?" or offering their guests coffee or tea. Practical conversation (talking "business") is easier for them. They like to repeat emotional states - rereading books, watching movies that they have already seen and revisiting places they liked. They avoid movies, situations and people who give them a negative mindset, because they have a difficult time getting rid of that mindset. Constructivists use emotional anchors (carefully chosen music, books, movies) to keep or strengthen their internal emotional state.
Emotivists try to enter the emotional atmosphere of the conversation and they try to keep the emotion in the conversation positive. They can talk about various things they have no interest in or do not believe in simply for the sake of maintaining a "positive spirit". Talking business is more difficult and the conversation topic can wander off into emotional exchange. They try to get new experiences and new emotions, which is why they travel to new places and rarely watch movies they have already seen. In emotivists calls for action/requests are not critically estimated and because of it they can get overwhelmed by them. After getting into a theme they stay in that mode of operation for a prolonged period of time and have difficulty switching, "disconnecting" (and because of it try to avoid unpleasant requests).
So stop for a second and think about "where" you would be if you were of the other dichotomy... that is most likely where you will find your dual.
A constructivist might be nervous to enter an emotivist community, because those emotions stick around for a long time.
An emotivist might be intimidated to enter a constructivist community, because the emotions and "themes" change abruptly and quickly.
So in essence, the two dichotomies intimidate one another, and generally don't enter one anothers' communities.