The Seeker Build guide on Max Roll doesn’t provide enough detail about Hammer Jammer/Falling Sword mechanics. So I will try to provide the info here.
On the surface, it appears MaxRoll’s build guide offers no way apply Hammer Jammers, but this is false.
Hammer Jammers is procced by Falling Sword itself, regardless of the rune selected. Falling Sword has a built in stun AND knockback effect. As long as Falling Sword hits the target, the Hammer Jammer debuff will be applied. Use any Falling Sword rune that you’d like.
I choose Flurry, why? Because the rotating swords persist after casting Falling Sword, which means that any trash that was not hit in Falling Sword’s 14 yard radius has a chance to walk into those rotating swords and get the Hammer Jammer debuff, so you’ll likely apply Hammer Jammers to more mobs with fewer Falling Sword leaps.
The flurry swords do not work on elites, only trash, so ALWAYS make sure you cast Falling Sword on the elite.
Part the Clouds is viable too, but the stun only hits 5 targets, like 1 per second, so it’s not going to do a good job in thick density.
To further ensure the Hammer Jammers, I also took Iron Skin:Charged Up, which pretty much guarantees everything near me will be debuffed. This is overboard, you might miss an oculus ring – but you won’t ever miss a Hammer Jammers proc.