^^ agree. Its ment to be used with two reins I think. I would never use a leverage bit like that with just one rein, because if you just have the reins on spot 3, you better not have much contact, or your going to tilt the bit around.
I found this information talking about this same bit:
This is an excellent transition progression bit from the ring snaffle to the shanked bit. The low port offers some tongue relief and little or now palate contact. The low-leverage shanks have dees for multiple reins. "Sweet-iron" keeps the mouth wet and responsive.