the problem w/ the units in C4D is that depending on if you use inches or feet as units, your camera will be large in one case (using feet) in an, otherwise, identically building.
that is to say a 10ft tall space, if built as 120″ tall space using inches as units is closer to the default size of objects (200units) than a 10ft tall space using feet as units. It a difference of 120:200 vs 10:200…
I always use inches.