Duffy.. to be honest ...in the 12 ga you won't swee any difference between 8s or 9s. especially at skeet distances. In the smaller gauges below the 20 it makes a bit of difference...especially in the 410. But even there I use 8 1/2s sometimes. Mainly for windy days. In fact I was loading only that one size for quite a while and saw no difference in my scores. Even with a marginal pellet hit with 8's it will usually break a target. For something so fragile clay targets really are hard to break
So in the 12 and 20...8s are just fine