I relate to those of my core type the most, by a large margin. Instinctual stack doesn't seem to make much difference, except that those who are so-dom & totally different types (different core, different Jungian type) will seem quite foreign. I guess the closer someone is to my types, the easier I can relate to them.
I've met 4s, but not been close to many, especially 4w5s. I see from the outside now how withdrawn & hard to get to know we are. I find it hard to get to know them also; it's as if most have keep themselves just out of reach on purpose. I see how their faces look sad, longing, discontent, haughty, etc. I see them appearing refined, distinct & offbeat, but in a quiet way (not a showy way). I can see why people form the impressions of me that they do, and I get to see/hear others express impressions of them, which is interesting.
I relate somewhat to those of my wing, mainly 5w4, but some 3w4 also (if also, say, artists or NFs).
I relate to IxFPs & especially INFPs who are not my core type also. Most INFPs I've met & been close to were 9s, and it's an interesting comparison/contrast (very similar thinking; strikingly so....but different demeanors).
Being able to see myself in people now has been eye-opening & refreshing. I couldn't or wouldn't do it when young, when growing up, and of course I felt alienated & defective, etc, etc. I find it easier to relate to most people now, but when someone really strikes me as having similar demeanor or thinking, it's almost always a 4 &/or INFP.