A few points:
1. The reason it starts so easily is because the prop is larger than the single seat gliders and therefore spins up more quickly. This also means it spins down more slowly.

2. On the ground, extend the engine and then retract it and you will see that it can actually retract a very long way with no risk of the spinning blades hitting the doors. Perhaps you did not retract it far enough?

3. As I understand it, the use of decompress to stop the rotation is not going to work while the decompress is active (decompress handle pulled), but with the ignition off and the engine partially retracted a slow removal of the pulled decompress handle will act as a prop brake. A bit like using engine braking in a standard transmission car or popping the clutch too soon while trying to bump start a car and having it come to stop instead of firing.