For those still interested in correalating cognitive functions to X types, check this out. Notably the correalation still isn't 100% clear.
Thinkist: not optimist nor pessimist. I am primarily competent in the enneagram.
SX 9w1, SP 5w6, SP 3w4 | Split with the first two
Ti-Se-Si-Ni-Te-Fi-Ne-Fe. I'm always questioning this, particularly the Si.
Big 5/Global5/SLOAN: RCUEX