Hmmm.. Thinking now I'm more of an 5w4 sx rather than sx/sp, by this definition. (The sp tendencies as far as I express tend to be more residual of the Five in general, rather than needing to be distinguished additionally by the sp marker.)
Especially as I've aged, I've moved out of sx/sp toward a more pure sx functional mindset. The first two paragraphs in that description fit me very well. Basically, the type is in extreme tension (much as is sx/sp, but I think 5w4 sx/sp is overbalanced as described to the detached end of things).
sx/sp mentions about having little regard for other's opinions and labels it as an "so" concern. While "so" is concerned about it, "so" also tends to be broad and shallow in the connection -- it's a social network, not necessarily an intimate network. I do care what others think relationally, but my goal is far more sx when I connect with people; the Five leads to an awareness and detachment, a resolution that others need their space and only enter intimacy out of their own choice, but the sx aspect ... which it can endure a relationship with boundaries... seems to always be disappointed when those boundaries are drawn and no more depth can ever be expected.