I am convinced that there is an inherent difficulty for an experienced motorcyclist who is an inexperienced helicopter pilot as regards throttle control.
I had amassed probably well in excess of 100 000 miles of emergency services motorcycling when I came to do my PPL(H). Despite it being the "wrong hand", so to speak - which was my instructor's argument against it - I found the instinct to roll the throttle the opposite way was overpowering. Now, riding motorcycles far less frequently than I fly, I feel I have mostly overcome the problem, but in an emergency? I'm not so sure.
DBChopper