Where do I put impale?

Have you tried shield charge for clear? Should scale similarly to shield wall. Impale needs to be applied with a strong hit to work effectively.

I've seen people using impale in their shield wall links. I believe it's the hit from fortifying cry that then extracts it. I'm not entirely sure of the mechanics so I haven't used it. I gravitated towards stuff that I know is up all the time.

When doing pinnacles I use Rapid Attack 2, Heavy Swing, Heft, Concentrated Area, and Bleed IV. I don't have much investment in bleed, just the two Empowered Attack nodes that also give bleed chance, but with incision from Bleed IV it is up pretty reliably. I put bleed 3 on sunder to guarantee a weak bleed on bosses to activate bleed IV damage, but bosses are usually bleeding before I sunder.

Clearing / Maps I use Ahn's, Kaom's, Aktali (whatever lifetap one is called), Rapid 2 and Heft or Heavy Swing.

Not sure if these are optimum but with a good shield late game your damage is insane no matter what you do I think. If you're just getting towards maps I'm guessing you just need to update your shield. 1300+ armor is a good goal for early / mid endgame.