For a normal 2-layers 3-phase winding, the number of coils is 3/4 of the number of armature poles. This is valid for both axial flux and radial flux generators. But you know that special windings exist, like used in the hoover board motor, for which you have 27 coils and 30 magnets so the factor is 9/10.
The number of preference positions per revolution is much larger than the number of armature poles. For instance, if you make a 12-pole radial flux generator and if you use a stator with 36 slots, you will get 36 preference positions per revolution (if the magnet sleeves aren't skewed). But if you make a 4-pole radial flux generator and if you use a stator with 36 slots, you will also get 36 preference positions per revolution. So the number of armature poles can't be derived from the number of preference positions per revolution, especially if you don't know if the generator has a 1-phase or a 3-phase winding and if you don't know the number of stator slots. You have to open the generator to be sure. For a 1-phase bicycle dynamo, the number of preference positions is equal to the number of poles.
