Mart,
Do you have any section drawings available for X2 blades? ... My heli performance program can now flap a single rotor to equality, so I'd like to see how X2 lift/downwash looks with cyclic trimmed for forward flight.
You have previously commented on the coaxial-ABC operating in an autorotative state. You may therefore find this report of value, due to the large stall region at the root end of the retreating blades.
Observations in flight of the region of stalled flow over the blades of an autogiro rotor
Dave