Paul, With either seat the top point of the pyramid of traction control is the seat/driver. The bottom is the tires contact points. The taller the pyramid is will increase the amount of vertical force upon the contact points when trying to change direction.
A lay down seat set up would need narrower and shorter contact points in order to try and equal the vertical force that a sit up seat would have. At some point in width and length decreases it would not be able to produce as much vertical force upon the tires.