Hi David, Spinner spirals eh, nightmare
, some skins have two places for the spinner, one for when it's static and the other for when its spinning, thats probably why your seeing that effect one way to test it is from an outside view slow down your in-game time and watch it change.
And then there are the spinners that are split into thirds...ekk, anyway you could to with using the panel finder overlay jpeg to layer over your skin then you can find where it is, what aircraft are you skinning, a ME 109?