I think xSTj is clear. He seemded more "serious" to me than the LSIs I know; they would be more likely to appear to "think out" their sentences and articulate their thoughts intentionally, while this guy seems to shoot from the hip, explaining the relevance of whatever the conversation turns to, to his system, as opposed to directing the conversation in a particular direction. He responds quickly and forcefully to every question, making no attempts at humor or lightheartedness other than in admitting his own personal simplicity. He also seems to value Ne, and "holding the universe in my head" sounds like Te to me.