I'm not backpedalling. You can sit on any side you like. Just don't fool yourself that there's an aerodynamic reason for it.
I may not fly helos for a living, but I do have an aeorspace engineering degree and 10 years experience as a Flight Test Engineer for various companies including 7 years with rotary wing outfits. I can guarantee you that there's no technical reason for pilots to choose one side over the other except for the human factors reasons I've stated above.
By the way, does your Astar not have a trim / mag release system? That'd be much more effective in countering any control forces than changing seats.