I have tried StillPoints Ultra SSs and Ultra Fives under three different speakers and often tried three versus four. The speakers were the Tidal Contrivas, the BMC Arcadias, and the LSA1 Statements. The latter are monitors and the SPs were used under the stands with the SP OEMs under the speakers.
My conclusions were that all speakers were improved with the SSs but never with the then available version made with aluminum and four were clearly better than three. Then Ultra Fives came along. The Fives are clearly superior to the SSs but are so big as to discourage use under components. Again four are clearly better than three. I use SP Component Stands under my monoblocks and my turntable with first SP SSs and later SP Fives mounted on the Component Stands. The SSs were good but the Fives are dramatically better. The same is true under my Bergman Sindre turntable.
I should note that four are much better if you take great care to be sure all four are equally in contact with the component or speaker. And yes, five are even better.
Finally, there are the Ultra Minis. They are quite small, effective, and cheap. I cannot hear any difference compared with the SSs. Comparing the Fives with the Minis is difficult given the size of the Fives. As the Fives have 5 of the SP technology in them, I doubt four Minis would be in the same league as four Fives. Maybe twenty Minis would rival four Fives.