I will just add another 360 unlatched canopy experience for the records.  I know there are differences in all aircraft and I will not debate the pitch oscillation, be it cause aerodynamically or pilot induced, which are very easy to induce in these aircraft.

I was pilot flying from the right seat, full fuel max gross 2 adults.  Running before takeoff checklist, left canopy open because of an aircraft on final.  Took off, gear up, noticed noise and instantly realized it was the canopy.  Simply, entered the downwind, flaps and gear as normal and landed.  Closed canopy, re ran checklist and took off.  Did not notice any pitch oscillation or change in handling.  I will add this particular 360 do not have any pitch change when adding flaps.  It has the mkII tail.  Other 320's i've flown have a significant nose down pitch moment when adding flaps.  I do not know if this is because of the small tail or rigging.  The owner of this plane has also forgot the canopy once before, while solo and did not have any handling issues.  Each of these planes are built differently, so whether or not Pilot induced oscillations could lead to a coupling of the canopy moving up and down and that leading to rapid changes in the airflow over the tail affecting pitch control, could possibly happen.  Just my story for the mix

Luke Alcorn