None. Never shot skeet in my life.
For me, when I want to practice wing shooting I go to a couple of the local farms that have lots of pigeons hanging around. Farmers tend to hate them because the eat a lot of grain meant for stock and they make a mess with their droppings so getting permission to shoot them is pretty easy. You have to be careful around buildings and livestock but once you prove you are a responsible hunter I find farmers will mention you to friends which means more shooting to be had.
Besides, pigeons twist and flare like doves which skeet doesn't and you can also eat them. Pigeon breast is really good on the grill and I've never found a clay target that was good on the grill. Plus, in most states feral pigeons are classified as a pest and you can shoot them year round with no bag limit. Problem solved.