FWIW:
Main Rotor is what sticks out furthest from any helicopter, all around the helicopter, with the exception of the tail section and tail rotor on most helicopters. Hence, MOST likely point of contact during a midair. (For tandems like Chinook, you are back to Main Rotor is what sticks out furthest from any helicopter, though the nitpickers will point to refueling probes on some helicopters sticking out a bit further).
perhaps a relative sketch of both planes considering their flight path, hovering, climb, path angles, etc. might close some speculation on all sides.
I won't hold my breath that this ever gets into the public domain