Yo-Yo, with a 120kg pax in the rear seat you get near neutral stability. Without the 120kg passenger in the rear seat how much stick movement would be required to perform the same loop? More/less or the same stick movement?
bbrz, I find it highly unlikely in an aircraft of this size with tandem seating, there is no noticeable difference in handling and/or pitch stability with the extra weight of a pax in the back seat.