I have N1,2, and 3 simply for "/focus" after I already have hit my big button to have the clones target the main characters target. Then N4,5, and 6 are "/cast [target=focus] polymorph". That way, after you Poly, you can hit your big assist button and DPS away until the sheep breaks and hit your N4,5,or 6 if the sheep breaks and it will automatically cast Polymorph on the previously focused target.

This is all assuming that you're targetting mobs by doing "/assist MainCharacter" rather than making each mob a focus and casting all your spells that way.