In my large outfitter tent, we've used the radiants on the propane tank style. But this is in a large tent (14x17 with 9' ceiling) We always had a low spot open at the door (air would leak in) and the eaves of our tent are open at the top, so we always have an air exchange going. Even thoug, we dont run it when we are sleeping.
I have a small Paulin PUP that I've used in a small ice fishing shanty. It uses the small propane bottles. It has a low Oxygen depletion sensor. It would be too small for a 200' tent, but other Paulin heaters may have the same type safety devices. I'm no expert, but CO is the issue, not low oxygen (just something to keep in mind).
I've used the radiant heaters up to around 8500'.
AJ