You can quote Marco Rämisch, it were 500 ears and they said their universal fit 497 of them.
However, fit is one thing. We are not on stage performers. We think of in-ears more than just a tool or even a necessity. I imagine that some of those will say "yes, it fits" but that does not mean that they are comfortable for extended use or even mean that there are no sound issues because of a weird ear canal. So I am guessing that we enthusiasts are a lot pickier.
In case your ears are weird, you can still go for the LivePro 3 (CIEM version of StageDiver 3).