Thanks, and sorry I was slow to catch this. The EV Zero should be able to fit into helmet vents, arguably better than other frames since there's a bit more give to handle wider spacing if necessary. At worse it might might be as secure therefore, but right now I'm trying it with one of my helmets (Cratoni Terron) and shaking it. Doesn't seem to really slip. Tension is sufficient and lacking the presence of being an "end weight" helps. In casual use for pit stops I don't see this practice being an issue.
Unless you're doing EPO and getting post-dosage spasms.
Just my Head Shake Test spasms!!
I can't imagine them not fitting in one of my Giro's...What about beating the hell out of the top lens edge when they're stuck in the vents upside-down and I'm walking around for a few mintes. No top frame like the Radars!