I haven't looked at all the space occupied by the motion of the pulleys, but I don't think it is much beyond the dimension of the platform. I suppose it depends on where on the platform you are standing.

Sweat radius? Well, I'm a heavy sweater, and the entire platform gets wet. I usually lay a towel on it so that I won't slip.

Good question....the sweat radius for me depends on intensity. Longer distance moderate, I usually sweat right on the platform. Higher stuff, it flicks off my arms and creates a line of sweat for about 3 feet behind me