I'm running four Knights at 1850 (Warden, Paladin w/ Stormspear, Paladin, Errant), with 315 pts to spare for allies. So far, I've run Space Wolves and Cult Mechanicus as my allied contingent. SW: Rune Priest w/ Meltabomb
2x Rhinos with 5 man Grey Hunter packs, w/ Meltagun
Cult:
Dominus
3x Destroyers with Grav
and 45 free points to spend on further turret weapons or a relic. Its fun to play, but not extraordinarily good. Dropping one of the Knights seems like the best avenue for switching things up, giving me points to pick up some Skitarii Vanguard or Kastellan Robots and giving my opponents something else to shoot at with their anti infantry weapons. The Destroyers were amazing with a Dominus tanking all of that fire. That 2+ armor save is fantastic with 3 wounds, and it would have been even better if I'd remembered he had feel no pain.