I don't believe I have Si in my ego (and anyway, my example should be taken with a grain of salt, I wasn't in a good mood yesterday and that might have affected my mental faculties). I don't relate to the descriptions of Introverted Sensing (in the ego position) at all, maybe except for the desire for aesthetic pleasures. I don't even understand what my inner states are, and one of my peculiarities is that I find it difficult to appreciate all that is sensory. For example, eating alone does not satisfy me. I have taken to reading a book or browsing the internet while eating. Besides, I think my parents might have been Si valuers and in comparison to them, there's a stark difference. It's discernible. I would expect an Se base to be in tune with his inner physical states and at least attempt to be healthy.
Now that I think about it, your statement about how an Si HA would behave rings true with me. I usually have no idea what to do with my body and that's why I invariably flock to sites like WebMD whenever I suspect an illness. I also have a friend interested in medicine whom I often consult for advice on such matters. This behavior would always irritate my parents, who mistrusted such external sources of information.