If you can get within range then yes it should work. You'll want to be very select in your shot placement for the halibut, otherwise you'll either be taken for a ride or see your gun being dragged off. Any spinal shot will immobilize the fish from the shot down, allowing you to finish it off with ikejime or gill pull.
Your tip selection can be equally important depending on your environment. A broad 2-wing spear head won't sink into the sand as readily as a thin breakaway tip. This can mean shooting a halibut, not having it penetrate far enough to stick, and losing a wounded fish. On the flip side of this, a thinner spear head means more emphasis on shot placement if you need a kill shot. It's also a lot easier to completely blunt a thin spear point if you over power your shot into a rock.
You'll fine more indepth answers on spearboard, but this is what I know. I'm pretty novice at spearfishing.