Melbguy1, I got my information directly from Paul Wakeen owner of Stillpoints but it was before there were the Ultra bases. I was doing a review of them, I did a comparison one time of Ultra SSs as they do allow some height adjustment. They definitely sounded better with the taper toward speakers as the technology is at the hard hat (tapered) end.
Since three points define a plain, anytime you use four, one will typically not in contact, so you would need some method to get contact. Incidentally, in my experience, four Ultra on everything are much better than three. And this is not subtle.