This is at least the second time you have made this comparison and I'm afraid it doesnt really work. Style of shoe is style of shoe. Size of shoe is size of shoe.
The Zero is the style and it comes in one size of nozzle. Yes, there are various tips that can help with fit but if the nozzle is too big with the smallest tip then it is tough luck on any buyers that this is too large for. And that is a chunk of people. How much neither of us can say.
Shure take a different approach- tiny nozzle and tips that will allow fit into larger ears. Up to a point.
The Zero fit me with the right tips but the large nozzle combined with the overall shell design aint a good recipe for a secure fit for quite a few people .
I suspect no one has meaningful data on the quantity of users that this or any IEM that is too big or too small for but please stop dismissing legitimate points with the "not many" argument unless you have some data.
For me too, the nozzles are excessively bulky (6.77 mm) but this is not the reason.
As for my ears, I always use the largest tips provided, the reason is not the diameter which is similar to that of my Intime (6.15 mm), but the insertion depth of the tips on the IEM itself which in my opinion is excessive (6mm! 4.90 for Intime).
This makes the tips too stiff, preventing them from conforming to the irregularities of the ear creating very uncomfortable pressure points for some (myself included).
My luck is that I don't find them interesting from a sound point of view, even if they are better than the usual CHI-FIs released weekly. The problem is that I'm trying to give them away (as I always do with IEMs that don't bring any added value to my collection) but it's not that simple, since I'm not the only one with comfort problems.