[Chris_Byler]

I thought the way to use archer decoys was to put them in front *and to the side* of your real troops, so they don't actually get in the way, but they're still nearer and thus targeted first. Since the slaves have 0 prot and are not buffed, they will take more damage. By the time they break, hopefully your real troops are within a round or two of reaching the enemy (or already have) and the dwarves are tired.

KO, in addition to the wooden warriors suggestion, you might also try mind hunting the dwarves with moon priests.