How to convert a PPL (Gyrocopter) to a PPL (Helicopter)?
In the US, Gyroplane and Helicopter are class ratings within the Rotorcraft category. FAR 61.63(c) specifies that the addition of a class rating does not require any specific amount of flight training time, and no more total experience than would be required for the gyroplane rating you already have, so the question is moot. All you need is an instructor willing to sign you off and to pass the abbreviated practical test.