One thing that puzzled me in horde combat is "What is the point of damage".
Invariably the damge the SM will do is going to be way above armour and toughness (and pen means armour is useless anyway). I aprecciate hordes of other creatures may make a difference, but in reality a hit is pretty much 1 magnitude.
So I allowed damage and for each 10 he rolled (on a successful righteous fury) allowed 1 extra magnitude of damage. I explained this down to either a well placed shot destroying a roof killing people, a melee attack ripping someone in two and demoralising the hordes, and after the initial couple, asked the players to describe their righteous fury to get the extra magnitude points of damage.
All in all it worked quite nicely.