Yes, mix out the pitch/yaw and roll/yaw coupling. That will help all around and present a much better flying airplane. It will help your stall turn a bit, but this airplane needs a little lead too and sometimes a good shot of elevator to keep the nose from tucking or lifting on the rotation.

For positive snap it needs very little elvator. Negative snap is normal. On positive barely blip the elevator and it'll snap quickly and cleanly. OR, the other way. Flying a medium speed, not fast, input a good dose of elevator and just as it pitches hard rudder, NO aileron, and it will truly autorotate. Remember, accelerated stall then rudder gives the real autorotation. Too high a speed and the airplane simply will not stall cleanly for a real autorotation snap. Don't see many real snaps today. Not like the Pitts where you see the nose come up sharply for about a quarter second and then the wings corkscrew around. Watch some full size airplanes snap roll. Nose up, then rotate. That's all this one needs too.

Spins are different because of the incidences and wing offsets relative to each other and the center of mass on the airplane that change the way the wings work together. Its normal. Some bipes like it inverted, other positive, some are OK both ways (very liberal, huh).

Mark