hmm easy? it's time consuming a lot
if you want i real easy
just go for paladins/rune mages/orc shamans
let the rune mages spam hallucinations and stuff on shamans/paladins
and just blast their army away+kthau and baal)
if u ever lose some troops just let the paladin resurrect them or just a hallucination to do it
by this way all can just attack and u can prevent him from spawning anything by placing totems
and you can even use some more level 3=4 units to your things
just make sure they surround the paladin
and just quick rape the bosses/units
it goes faster than your way of doing it