I like autogyros and have built a number of 1/2a versions over the years. Last year at my club’s 1/2A day I unveiled my Coaxial Rotor Gyro. It uses an AP .061 with throttle. Blade diameter is 16 inches. I used the coax rotors (they rotate in opposite directions) to compensate for the un-equal lift that rigid rotors produce. In a rigid rotor setup, normal for CL gyros, the advancing blade generates more lift than the retreating blade. This causes the gryo to roll towards the retreating blade. The coax system cancels the effect and the gyro looks better the air.  The AP has so much power that I wish the gyro was about 20% bigger.