I took a charger to act 4 hell in a tourny but never got round to finishing him.
Skillwise you pretty much have 2 options:
1: Max damage route - Max Charge & its synergies. This gives you big hurty damage, but you could get in trouble vs PI's and in narrow places where you don't have the room to charge (Maggot Lair anyone?)
Oh - A few in fanaticism don't hurt either
2: Balanced damage route - Max either charge and one of its synergies,or max the synergies with just the 1 in charge. I don't have the #'s in front of me to see which is more effective. This still gives pretty decent damage, plus you have points spare to sink in either vengeance (no more PI probs) or zeal (maggot lair)
You'd probably still want to use fanaticism here.
For a merc I went with might (I was going for max dmg) but A HF merc would slow things down a lot and make it easier to line em up for a charge.
For equipment you obviously want a big hurty weapon (who needs block when you're doing 10k+ dmg a hit)
You can always charge away before the monster gets ints counter-swing in anyway.
Try to get something with a smaller range to you can charge at things that are near you - polearms have nice damage, but 1/2 the time you can't charge with them as enemies tend to be in normal attack range.
I was using heart carver for a while as it was the highest damage weapon I had, and it worked really well.
Tactics:
Pinball anybody?
Charge into monster pack, charge out at random monster, charge back in...try to separate the monsters into individual groups so you can bounce your way around
I had a great time with the build - only problems i ran into were PI's as I didn't have enough elemental dmg to take care of them.
Just for kicks I equipped mine with an ethereal hellslayer (~1k max dmg) I had laying around just to see what the damage was like.
I can't remember the #'s, but with max charge & synergies, max fanaticism and a high level might merc it was pretty insane.
Even better once I tripped that combat shrine too
Good luck
