FC is actually a lot easier than most people think. I'll give you my gear and atma that kills most things in one shot.

Merits: 8/8 GA, 8/8 STR, 12/12 HP(really does help in that OSHI situation)

Gear:
Weapon: Step up to Warlord's Axe or Widowmaker, Ukonvasara is the ultimate goal really.
Grip: Stop using Uther's Grip forever. Pole Grip or Claymore Grip or go home (Sword Grip is situationally better, ask someone who knows a lot about STP and x hit setups before using)
Ammo: Yes.
Head: Twilight Helm is the absolute best for FC. Otherwise Hecatomb Hat/+1 > AF3+2
Body: Yes. Only way up from Grim is Grim +1
Legs: Yes. Hachiryu is the only thing you can put here, or a well augmented Adaman/Armada legs.
Hands: No. Alky's are better, Heafoc are best.
Feet: Yes! Go for the STR+3 Aug on NQ, +4 on HQ. (HQ can get a total of 11 STR!)
Rings: Pyrosoulx2 is optimal.
Earring: That's what I use; STR+4 will be much better than Rvg. Earring though. Too bad it's like 2.5mil+
Waist: Beir Belt +1 > all
Back: Yes.
Neck: Ire Torque +1, Gorget MAY be better but I cant be asked to go make one right now.

Here's the kicker though;
Atma: RR, SS, Apoc (Should be using these anyway)
USE MIGHTY STRIKES AND BLOOD RAGE. DO IT. It makes Fell Cleave 100% Critical, meaning you WILL kill 90% of mobs in 1 hit. I regularly do ~5k with Fell Cleave+MS+BR. You'll get your 2hour back if you have good azure, or even amber since Revitalizers are quite common.

Good luck on your farming!

Edit: For hands Hecatomb can be better, but with RR and SS + Blood Rage you should be hitting cap, or getting very close.