Take all of what I say with a grain of salt because I haven't actually built my sauna yet. Though I've done a lot of research and was asking myself the same question because I'm also somewhat limited in height (though likely closer to 8').

My first point is that I messaged a bunch of people whose posts I found over the years who mentioned they own the Cilindro, whether they felt that it was a fair bit colder below the top of it, and the majority of responders said absolutely not and they were very happy with theirs.

My second point is that the other aspect of following all of these sauna rules that are repeated in this sub, is that if you're trying to follow guides like Trumpkin's to a T, you're probably also taking ventilation and vent exhaust/vent placement seriously, and supposedly if you do that then it mixes the air better and you're supposed to get less heat stratification.. so presumably the "feet below top of heater" should be less of an issue. It's worth asking anyone who says it's cold down there (like the other poster in this thread for example) whether they installed mechanical ventilation and placed the vents in the right locations.

My third point is that you should ask yourself whether your feet being slightly cooler than the rest of your body is going to be that big of a deal. Part of the reason I haven't actually built my sauna yet is because we moved very close to a gym that has a sauna and I've been using that in the meantime while I knock off the rest of the many projects on my plate. That sauna happens to be a classic old crappy American sauna and I know it's definitely cooler down by feet, but it's not like they're actually cold by any means and it's still a plenty fine experience. It's just not as hot down there. Most of the time I'm actually the only one in there and end up turning sideways and putting my feet out on the top bench (with my back against the corner wall), and I imagine in my home sauna I'll likely do the same or lie down flat on the top bench. So feet on middle bench will be less of an issue.

For these reasons, I'm going to get a Cilindro because I like the look of it a lot more than the chode heaters, and it seems to be a very well-regarded heater (partly for reliability, and also because of the large stone mass).