Trying to grind a weapon, need advice

A friend suggested I grind Twin Orochi for my bouncer, so I got it to +10 atm. Which hidden potential is better, Critical Slam or Warring Devastation Stance?

Warring Devastation Stance increases the power of Break Stance, but this doe not effect Break Stance D Bonus, meaning it only works when you are attacking breakable parts.

Critical Slam increases Critical Rate by 25% and then gives a Crit power boost of 17%/19%/22%. As a Bouncer (I'm going to assume Hu or Fi as the subclass), you can get a Crit Rate of 85% from Class Skills, which means with this Potential, you can have a (technically over) 100% Crit Rate, so the Crit damage bonus is always applied and you have no damage variance.

The way you phrase it makes it sound like crit is way better, although I was told that break stance is way better against enemies with breakable parts, which is almost all of them.

Let me add a bit more info, so you can make your choice:

Warring Division increases the power of Break Stance the Skill, ie. just the Skill called Break Stance, not Break Stance up or Break Stance D Bonus. At +30, that means that it increases the power of Break Stance by 60%, which means that Break Stance then gives a 216% multiplier instead of just 135% (1.35x1.6). The downside to this is that when you are attacking a non-breakable part (either because the enemy doesn't have any or you already broke them), you don't get any damage multipliers from the Weapon.

Ultimately, it comes down to consistency (Critical Slam) versus higher damage potential (Warring Division).

Yea, I opted to go for Warring Division. I'll just get another weapon to deal damage once all the breakables are broken, but that can wait until later.