Ftr, I think doing the switch from mbti to socionics is wrong, it doesn't make sense. J is J in both systems. The problem is that it's not that apparent or clear cut for all people - it's more like a spectrum. But Ni base should be P in both systems, cause it's an irrational function. Jung was describing IEI and ILI in his Introverted Intuition type, not INFJ and INTJ - MBTI fucked it up. SLI and ISTP are the "mechanics" in both systems, it's not like ISTJ is called the "mechanic" type, it's called the logician, thus LSI, hence it should be Ti dom. They got the functions for introverted types wrong.