magnetic fields are roughly spherical, composed of two toruses (torii?) whose centre is the pole, at best you might say lemon shaped, or maybe apple shaped is more accurate because deflection is weakest at the poles

so, if you are using a magnetic field as a shield, its shielding is stronger everywhere except the poles, and the shape of a pair of cylindrical magnets makes them best to orient horizontally like a choker bracelet, the strong attraction areas are then to your left and right not in front of you, that's where the greatest amount of perpendicular flux is, ie, the shielding effect