With the different shims, it's impossible to know how it shoots for you out of the box. Go shoot at a patterning board and make a determination where it's shooting. For skeet people generally use a 50/50 ratio (50 percent of pellets above, 50 percent below the aim point). For trap it's anywhere from 60/40 - 80/20, and for sporting a good starting point is 60/40. In trap they do that because the bird is always rising, and they don't ever want the barrel covering the bird. They "float" the bird on top of the barrel. In skeet, the bird is crossing, so normally you want to cover the bird and pull the trigger. With sporting, birds can come from any direction or orientation, so they set it up slightly high so you don't cover rising birds, but still can get underneath falling birds. I set up my waterfowl guns slightly high, say 55/45 or 60/40. I shoot a lot of sporting clays and want my sight picture to look the same.
Long story short, go pattern your gun and adjust from there.
I'm as good once as I ever was isn't your theme song OG. I hate to burst your bubble.