Last year I took a class to determine my Enneagram number. I’m an old hand at Myers-Briggs, with its 16 types, but this nine-number circle with all sorts of arrows going back and forth was a new system for me. Thankfully the teacher, Suzanne Stabile, had a teaching style I understood well. It turns out we are the same type.
Some of us reside in the heart (or feeling) triad, as Suzanne and I do, and some in the head (or thinking) triad. My guess is Thomas would belong in the third triad.