According to Reinin :
Carefree = EN + IS
Farsighted = ES + IN
According to Talanov :
Carefree = Sensing has a low level of excitation (higher sensitivity)
Farsighted = Sensing has a high level of excitation (lower sensitivity)
This explains why Introtims may still be stimulation-seeking. When Rick wrote that Introtims had a lower optimal level of stimulation, and Extrotims have higher, he was wrong.
Carefree types are more sensitive to external stimulation. They feel the need to have less than Farsighted types, which feel the need of more external stimulation than Carefree types.
btw, MBTT was wrong too.