I don’t think the NA-R5 housing has a cold shoe mount, but if there’s a way to add one, that could be an option.
So this is what I’m working with: an NA-R5 and a 170mm dome. I occasionally go through tight swim-throughs while freediving, so minimizing drag is important. I’m also thinking that mounting the GoPro directly on the dome will center its lens with the camera, rather than having it offset on a ball mount. If I use one and extend it toward the center of the camera, it will add to the overall size of the setup, which I’d like to avoid.
At the end of the day, a little extra drag won’t be a dealbreaker, but I wanted to see if anyone had better ideas.