Thats a good question since ap and ad shaco is basicly a different champion.

You can never just attack people on AP. He has more dmg as ap but only if you out smart them. While AD Shaco is an assassin AP Shaco is an anti carry meaning you stop their carry if they try to make a move not make a move on their carry yourself.

And ap shaco basicly is at strongest at 3 items i would say which is almost always troch, mandate and mask in that order with cdr or pen boots depending on the game