Well SAS, I thought it would be interesting to see how performance would compare if only one variable was changed, in this case, an extra rotor. To introduce overlap (proper practice or not) would not be the point of this exercise and would thus yield results not answering the original question.
However, it is indeed a good idea to have some overlap due to practical considerations as the ship will become super long if no overlap was present.
For side by side rotors the total flat plate drag area of the airframe would be much higher if all things are kept equal due to the outriggers on which the rotors ride. The machine itself would also become even bigger because it now also has a tail to park somewhere on the flight deck.